DAN JONES: For me a great British castle is a fortress, a palace, a home.

And a symbol of power, majesty and fear.

For nearly a thousand years, castles have shaped Britain's famous landscape.

These magnificent buildings have been home to some of the greatest heroes and villains in our national history.

And many of them still stand proudly today, bursting with incredible stories of warfare, treachery, intrigue and even murder.

Join me, Dan Jones, as I uncover the secrets behind six great British castles.

This time, I'm in Carrickfergus, exploring one of the oldest and longest-serving military strongholds in Ireland.

Carrickfergus Castle takes us right to the heart of the long history of violence and hatred between England and Ireland.

Neighbors, torn apart by wars over power, religion and national identity.

Today, Carrickfergus is a quiet town on the coast of Antrim, a short drive north of Belfast.

It's part of Northern Ireland, a country joined together with Scotland, Wales and England to make up the United Kingdom.

But traditionally, this British region in the north of the island, overlaps with the Irish province known as Ulster.

(PEOPLE SHOUTING) This is where Britishness meets Irishness, and Protestantism meets Catholicism.

(WOMAN SHRIEKS) Over the years, the clash of those identities has caused terrible bloodshed.

(INDISTINCT CONVERSATIONS) The story of the troubles in Northern Ireland goes back nearly 900 years to the Middle Ages, and it all starts here in Carrickfergus.

Today, when we think of Ireland's troubled history, we tend to think of Belfast, but back in the 1100s, Belfast was just a tiny hamlet and it was Carrickfergus which, thanks to its key geographical location, was the most important town in Ulster.

And the first person to spot the major military and political potential in Carrickfergus was a maverick young knight called John de Courci.

de Courci was the second son of a lord from Somerset, in southwest England.

He had no claim to the family estates, so he decided to seek his fortune elsewhere.

Ireland was ripe for the taking.

(SOLDIERS SHOUTING) The English had traditionally left Ireland alone.

But de Courci was born at the right time.

In the 1170s, the king of England, Henry II, was raising an army to conquer Ireland for himself.

de Courci was part of that invasion force which swept through the country, taking key regions and towns.

Whilst others captured the south and east, de Courci set his sights on the north.

He assembled a small army of 22 knights, and 300 foot soldiers, and marched north to the province of Ulster.

He put the Irish to the sword, overthrew the native Ulster chiefs and claimed lands on the east coast.

(SWORDS CLANKING) de Courci had conquered eastern Ulster, and now he needed somewhere to make his stronghold and his principal residence in Ireland.

He chose this small strip of rock overlooking the Irish Sea.

It was surrounded by water on three sides, the perfect defensive site.

de Courci built a large stone keep, with a high curtain wall and gate.

Within the walls, he built a great hall, where he held court as the self- appointed ruler of Ulster.

If you were an ambitious, thrusting young noble like John de Courci, this was the virgin territory, really.

Very much so and, um, I think John de Courci was very ambitious, very, very clever man and very brave.

Um, he took on... He was going basically into the wilderness to find this wealth and to fight battles in very unknown territory, so you could come here as a very poor lord or as younger son and really make a fortune.

If you were brave enough to do it.

JONES: de Courci realized it was all very well building this castle, but to really cement his power, he was going to have to make peace with the locals, which he did so effectively that contemporary documents refer to him as Princeps Ulidae, Prince of Ulster.

This was a big problem for his new king back in England.

By 1205, Henry II was dead.

His son, King John, was on the throne.

For a while, de Courci had proved himself useful to the English Crown, enforcing the law and raising taxes.

-Rent of half a shilling.

-MAN: Thank you, my lord.

But now John realized he was getting too rich and too big for his boots.

And if that wasn't enough, de Courci did something really stupid.

When he was here, he started -minting his own coins?

That's right?

-He did.

Yes, he did start minting his own coins.

This was seen by the King John, back in England, as a real threat to his authority.

At the time, coins were seen as a real symbol of power.

Uh, the King would have minted coins to show that he controlled all the trade and commerce.

So, when John de Courci decided to mint coins, he was really making a declaration of independence.

JONES: He's saying, I'm the person who controls commerce, who controls power in this part of the world.

MCALLISTER: Absolutely.

JONES: Almost like he's the King of Ulster himself.

MCALLISTER: Indeed.

That's exactly what he was saying.

And John was a very mean and vindictive man.

He felt very insecure in his place on the throne.

And he would have been absolutely outraged by such a declaration of independence from himself.

It was just unfeasible that a mere knight could do this kind of thing.

And can we see the coin?

We can see it here, in this little box.

It's very, very small.

It's just a tiny fragment, really now, but you can still make out it's silver, isn't it?

It's still silver, but with quite a high percentage of \ tin in it, which makes it very brittle.

It's amazing to think that out of this tiny coin arose so much trouble between King John and John de Courci.

MCALLISTER: Absolutely, he was making such a statement with this tiny coin.

It was a real gesture of defiance to King John.

It's fascinating.

It's very small, but it's a very, very powerful symbol.

JONES: At first, John asked another nobleman to force de Courci out of Carrickfergus.

But eventually, he realized there was a much more effective solution.

John decided to do the job properly.

He came over to Ireland and took the castle into royal hands.

de Courci's armies had been defeated.

He was stripped of his lands and power in Ulster and thrown out of the castle.

But King John wasn't finished yet.

Work began on building the castle's middle ward and four new towers.

It was all surrounded by a massive new curtain wall which strengthened the castle's defenses against attacks from land and sea.

To the Irish chieftains in Ulster, Carrickfergus was now an English town, right in their midst.

In return, King John saw Ulster as the Wild West, an uncivilized place inhabited by savages who needed to be kept firmly at arm's length.

And that attitude was captured by a chronicler who visited Ireland alongside John and wrote about its conquest by the English.

He writes of the Irish, "They are a wild and inhospitable people.

"They live on beasts only and live like beasts.

"They have not progressed at all "from the primitive habits of pastoral living."

It goes on and on, he says, "While man usually progresses from the woods to the fields "and from the fields to settlements and communities of citizens, "this people..." That's the Irish.

"...despises work on the land, "has little use for the money making of towns, "condemns the rights and privileges of citizenship, "and desires neither to abandon, "nor lose respect from, "the life which it has been accustomed to lead "in the woods and the countryside."

By the time John died in 1216, Carrickfergus Castle was a menacing military presence on the coast.

And it needed to be.

Because across the Irish Sea, another enemy force was gathering.

And their number one target was Carrickfergus.

In the Middle Ages, Carrickfergus was the most important town in Ulster.

And its castle was a sign of the daunting military power of the invaders who occupied it.

But because of its position, this castle was also a place to play out struggles with their origins in other parts of the British Isles.

In the 14th century, that's exactly what happened.

Carrickfergus Castle has been besieged plenty of times over the years.

It's at the heart of the story of the English conquest of Ireland, so it's the key to understanding the tumultuous relationship between those two countries.

But it wasn't always the English invading.

In fact, this castle was the pivotal point in a Scottish invasion of Ireland.

In the early 14th century, the Scots were fighting a vicious war of independence against England.

They were led by Robert the Bruce, one of the greatest military leaders in their history, who was determined to be recognized as King of Scots.

(SOLDIERS SHOUTING) (SWORDS CLANKING) For Robert, smashing the English on his home soil wasn't enough.

At Carrickfergus, he was about to prove it.

In 1314, Robert the Bruce won a famous victory for Scottish independence at the Battle of Bannockburn.

Bruce, eager to follow up on his success, decided to open a second front against the English, here in Ireland.

Robert already had a connection with this part of the world.

He was married to the daughter of the Earl of Ulster, so he knew the significance of Carrickfergus Castle all too well.

When you stand here on the coast of Antrim, you really understand why Bruce thought he could invade.

Because just out there, very clear on the horizon, is the Mull of Kintyre, that's the coast of Scotland.

And it looks, not quite close enough to swim, but certainly only a few hours' sail on a nice clear day like today.

(INDISTINCT CONVERSATIONS) To oversee his invasion, Robert chose another man who knew Ireland.

His younger brother, Edward Bruce.

(INDISTINCT CONVERSATIONS) Their plan was simple.

The Bruces would bring together all the Gaelic peoples in one mass, anti-English movement.

Bruce brought 6,000 men over in boats called Birlinns, which looked just like Viking longboats.

It would have taken a full day's rowing to get from Scotland.

When they arrived in Ireland, they set about allying with local families.

Their aim was to take Carrickfergus Castle and turn Ulster Scottish.

Edward and his troops landed at Larne,just north of the castle.

After overrunning the town, his triumphant army was on the march.

The first thing Edward did was to declare himself King of Ireland.

Then, he attacked Carrickfergus Castle.

Edward's army arrived in front of the castle in September 1315.

Inside, the small garrison watched thousands of Scottish soldiers take up their positions outside the walls.

Edward was confident of victory.

But there was a problem.

He didn't have any siege equipment.

So instead, he surrounded the place and waited.

A year later, he was still waiting.

(MAN COUGHING) The castle was stocked with descent reserves of food.

But the defenders inside had also been joined by townspeople fearful for their lives.

(MAN COUGHING) Inevitably, after months without relief, the food started running out.

The inhabitants were reduced to chewing on animal hides to survive.

(COUGHING) Edward sent messengers inside to discuss terms of surrender, but they never returned.

Accounts say up to 30 captured Scottish soldiers were imprisoned in the castle.

And not all of them made it out alive.

As the siege progressed, it's believed that the castle's starving defenders started killing and eating the prisoners.

The siege lasted a staggering 12 months, and by then, only a handful of the original occupants had survived.

In the autumn of 1316, the long siege of Carrickfergus Castle was over.

Edward Bruce had taken a magnificent prize.

But he wouldn't hold it for very long.

Ireland was in the grip of a major famine.

It was increasingly difficult to feed troops in the field.

Two years after capturing Carrickfergus Castle, Edward's weakened Scots-Irish army was annihilated by the English at the Battle of Faughart.

(GRUNTING) Edward was killed.

His body was quartered and sent to the four corners of Ireland.

His head was sent to the King in England.

Two months later, the castle that Edward had taken at such cost was recaptured.

Carrickfergus remained the key to controlling Ulster and now it was back in English hands.

And that's how it stayed for 200 years, when the castle was the center of a new war.

This time, a war of religion.

(MEN SHOUTING) In 1558, Elizabeth I became Queen of England.

She claimed to be queen of Ireland, too.

Elizabeth was a Protestant monarch, and she wanted both her realms to be Protestant as well.

And to achieve her aim, she planned to get rid of the Catholic ruling classes, by whatever means necessary.

But what started here at Carrickfergus Castle in the course of her reign, still divides Ulster today.

There were always people ready to ingratiate themselves with the Queen by seizing land for the Crown in Ireland.

And one in particular stands out.

Walter Devereux, Earl of Essex.

He came to Carrickfergus in 1573 with a force of 1,200 men, and began a notoriously bloody campaign in Ulster.

Essex was an ambitious, ruthless man.

And he was at the center of one of the worst atrocities in British and Irish history.

Whilst Elizabeth's plan was to strip the Irish of lands and power, Essex wanted to slaughter them.

(SOLDIERS SHOUTING) From his base at Carrickfergus, Essex divided the local clan chiefs and picked them off one by one.

Before long, every clan leader was either dead or had sworn allegiance to the Queen.

All except one.

The one obstacle remaining to Essex was a Scots-Irish clan led by Sorley Boy MacDonnell.

The MacDonnell clan were originally from Scotland, but they'd been settled in Ireland for generations.

Sorley Boy had fought in dozens of battles and had absolutely no respect for Englishmen like Essex.

In July 1575, Essex decided to drive Sorley Boy out of Ulster once and for all.

When Sorely Boy heard that Essex was on the attack, he sent hundreds of vulnerable people, women, children, the sick, the elderly to Rathlin Island for safety.

But that didn't put Essex off.

Straightaway, he hired the services of John Norreys and one Francis Drake to take a large fleet over to the island and flush out the vulnerable people hiding there.

Norreys and Drake packed ships with soldiers and firepower and set sail north from Carrickfergus towards Rathlin Island.

Their orders were to kill anyone they found.

Sorley Boy's supporters had taken refuge in Rathlin Castle.

Drake used cannon to soften them up.

Then Norreys ordered a direct assault.

Even when Sorley Boy's followers surrendered, the English showed no mercy.

Essex's men massacred 200 people they found hiding in the island's castle.

Then they scoured the rest of the island for between 300 and 400 more who were hiding in undergrowth and caves.

(WOMAN SHRIEKS) (WOMAN GRUNTS) Most were women and children.

Essex's men massacred them all.

(ALL SCREAMING) (WOMAN SCREAMS) Sorley Boy's entire family was slaughtered in the massacre.

Something Essex later boasted about in a letter to the Queen's secretary.

He said Sorley Boy had watched the massacre helplessly from the mainland and was likely to run mad for sorrow.

Given the horrific nature of the Rathlin Island massacre, it's hard to believe that Queen Elizabeth would have thought of this as something to be proud of.

But apparently she did, because she wrote a letter to the Earl of Essex asking him to congratulate John Norreys, and tell "The executioner of his well-designed enterprise, "that she would not be unmindful of his services."

A month after the massacre, Sorley Boy and his followers sought revenge.

They attacked Carrickfergus, plundered the town and ransacked the castle.

But it was too late.

Essex was gone.

Deep in debt, he had been recalled to England and died a year later from dysentery, aged 35.

The massacre was a turning point in the struggle between Protestant and Catholic communities in Ireland.

It would leave a deep scar in the memories of Ireland's Catholic people.

And it wasn't the end of English attempts to colonize Ulster.

Once again, Carrickfergus Castle was central to a vicious conflict between the two countries.

And this time, the Irish resistance sparked a rebellion which would have dramatic consequences across the rest of the British Isles.

Since it was built at the end of the 12th century, Carrickfergus Castle had attracted a stream of headstrong and violent English invaders to Ireland.

One of the most brutal of all arrived in 1599, and took up his post as the Governor of Carrickfergus.

His name was Sir Arthur Chichester.

Chichester was a famous soldier who'd fought against the Spanish Armada and sailed with Drake to the New World.

He had a reputation for bravery and ruthless cruelty.

Chichester is still in Carrickfergus today, buried just around the corner from the castle at the Church of St.

Nicholas.

This enormous tomb is a monument to one of the most important families in the history of Carrickfergus Castle.

They're the Chichesters, and we can see them here.

This is Sir John Chichester, as you can see he's lost his hands.

In life, he lost his head because he fell out with the MacDonnell clan, they chopped it off.

And legend has it, they played football with it.

And that led to his brother, Arthur, becoming governor of the castle and he's the really important guy.

Here he is, here, with his wife Letitia and between them, their baby son, also called Arthur, who died when he was two months old.

But what I love most of all is this inscription, which is the most wonderful piece of propaganda about the whole family.

And it says that, "Arthur, having suppressed O'Dogherty "and other northern rebels, "and settled the plantation of this province, "well and happily governed this kingdom in flourishing estate."

Which sounds great, but actually it wasn't as simple as all that.

Chichester looks very peaceful on his tomb, but in life, he was a real hate figure for the Irish.

He believed in brutal war tactics including starvation and scorched earth.

Like every Englishmen before him, Chichester used his powers to harass Ulster's leading Irish chieftains.

But his treatment here at Carrickfergus Castle of one powerful clan leader, Conn O'Neill, inadvertently tightened links between Ulster and the Scots.

Conn was imprisoned here after his men got into a skirmish with some men of Arthur Chichester.

It began over some confiscated wine and it ended with Conn locked up in one of the castle's dungeons.

Conn O'Neill was sentenced to death and thrown in this damp, dark dungeon to rot.

But he wouldn't be there for very long.

Chichester imprisoned Conn O'Neill in this dungeon.

Now, Conn was facing execution, so he was quite desperate.

So desperate, in fact, that he made a deal through his wife with a Scotsman called Hugh Montgomery.

The deal was if Hugh could bust Conn out of prison, Conn would divvy up his lands with Montgomery.

Hugh's escape plan was simple but ingenious.

He hid a rope in a block of cheese, and smuggled it into Conn's cell.

Now, Conn could then throw the rope through the window and escape down the castle walls to a boat waiting outside.

Now, Conn stuck to his side of the deal, he divided up his lands with Hugh, who was then able to bring his relatives over from Scotland.

And that started what would become the great Scots settlement of Ulster.

While the re-settlement of the Scots into Ireland wasn't official policy, it soon would be.

When Queen Elizabeth died, her cousin, James VI of Scotland, became James I, King of England, Scotland and Ireland.

Under James, a systematic policy of plantation in Ulster began.

-(GUNSHOT) -(MEN SHOUTING) Plantation had been used effectively by the English in the New World.

Settlers were imported to a foreign country where they took land from the natives and created English-speaking towns of their own.

To impose the policy in Ireland, James turned to Sir Arthur Chichester.

He was promoted from Governor of Carrickfergus to Lord Deputy of Ireland, the most powerful man in Ulster.

His actions started a sectarian war that would last for another 400 years.

Here outside the town of Omagh, this model plantation village shows us exactly what happened.

Plantation villages like this sprung up when the Crown seized land in Ireland and colonized it with settlers from England and Scotland.

Until Elizabeth's reign, it had mainly been the work of individuals, but in the 17th century, it became official policy that would divide Ireland forever.

Four million acres of confiscated land in six counties west of Carrickfergus was now handed to Protestant settlers from Britain.

There were strict conditions.

In most cases, settlers were banned from having Irish tenants, they couldn't sell any land to the Irish and they couldn't employ any Irish labor.

Today, we'd call that ethnic cleansing.

But that's not how James I saw it.

He saw the systematic replacement of Ireland's native Gaelic-speaking Catholics with English-speaking Protestants as a civilizing enterprise.

Initially the plantation of Ulster was a mixed success, but by the 1630s there are as many as 30,000 settlers and the population was growing rapidly because just under half of them were women.

So towns like Carrickfergus were flourishing.

By now, Carrickfergus Castle was unmistakably a symbol of English occupation.

It defended a Protestant town full of settlers living English lives in the middle of Catholic Ulster.

Before he died in 1625, Chichester ordered the building of a high wall around the town to keep the native Irish out.

And to keep the British settlers in, Chichester relied on fear-mongering and propaganda.

It was said that the English settlers were in danger if they ventured even a mile outside the walled towns because the forests and the countryside were crawling with native Irish rebels known as Tories.

The name came from the Gaelic word toraí, meaning pursuer.

They fought a guerrilla war against the settlers.

In return, they were seen as fair game.

Tory hunting was a popular blood sport that attracted many adventurers to Ulster, eager to join the chase.

Horrific sectarian atrocities were committed on both sides.

But here at the National Library of Ireland in Dublin, one incredible document shows how the blame for all the brutality was heaped on the Irish.

So, Gillian, tell me what we've got here?

This looks like the front page of a newspaper.

GILLIAN KENNY: It's a broadsheet printed in 1647 and what it is, is basically, a way of telling ordinary people of the events that were supposed to have happened in Ireland in 1641.

Especially in Ulster, where there were allegedly terrible massacres carried out.

So this is a very gory retelling of what actually that is.

JONES: Who was this addressed to?

KENNY: This was addressed to the general public.

It's done in a way to outrage people as well.

It's all about atrocity and of course, it's accompanied by an illustration for people who were illiterate.

They could just look at this and know exactly what it's about.

So it's a kind of list of really neat little examples of terrible things that have happened in Ireland.

It's almost like a, sort of,Twitter feed of atrocity, and they say some awful things that the Irish supposedly have done.

"They have hung up English by the arms "and then hacked them with their swords "to try how many blows they would endure before they died."

So the tone is quite evocative.

These stress quite a lot, attacks on the innocent, and it's, I suppose, they put it in a situation of Catholic versus Protestant.

In 1641, the Catholics rose up, and, um, according to reports at the time, started slaughtering Protestants.

JONES: In 1641, the countryside around Carrickfergus became a war zone when the native Irish rose in rebellion.

In the space of a year, up to 12,000 English and Scottish settlers were massacred or died of starvation after being driven from their homes.

The rising raged for 11 years.

So, when the English public at home read things like, "They have boyld children to death in Cauldrons.

"They hanged a women and her daughter in the hair of her own head."

This is being presented as fact, and people who weren't in Ireland would have thought, "Well, that's exactly what's happening."

KENNY: Exactly, and it's part of a tradition, really, of showing the Irish as barbaric which really begins in around the 12th century and continues through.

What adds to this is, of course, is the fact that by the time this comes out in 1647, to be Irish is to be Catholic and therefore, um, to be an enemy of the English state.

So that adds into that propaganda as well.

So, in a sense, the Irish doing this are in a way subhuman.

They are capable of carrying out these atrocities because they are very much non- English and not loyal to the English state.

And this isn't just a sort of document of horror designed to put the fear up the masses, is it?

This is actually calling for political action because it says here, "Recompense unto them double what they have done unto others."

That's a call for full on military attack, isn't it?

KENNY: Absolutely.

It's estimated between 1649 to '53, about 20% of Ireland's population died.

Um, there was... The rules of war didn't apply to soldiers in Ireland, so you weren't allowed to give quarter to the Irish when they were here, and genocide was smiled upon because it was seen to be just.

So if you put yourself in 17th-century terms, it's absolutely justifiable to behave as they did.

All of this propaganda being fed back to England about the ghastly acts the Irish had committed led to the sense that the Irish had to be dealt with.

But there is an argument, "Who would raise the army to do it?"

England at the time was in chaos and in the middle of the 17th century, King Charles I was beheaded.

(CROWD SHOUTING) England was declared a republic.

And at its head, was one of the most feared and ruthless leaders in British history.

Oliver Cromwell wanted to place Ireland firmly back under English rule.

One of his first actions was to send troops to Carrickfergus Castle.

Then, Cromwell's massive army terrorized the Catholic population throughout Ireland.

His military campaign scarred the Irish psyche for centuries.

But he wasn't the last English ruler to leave his permanent mark at Carrickfergus.

Because before long Cromwell was dead, the English monarchy was restored and Carrickfergus Castle was welcoming ashore another man who would change British and Irish history forever.

This time, he was Dutch.

At the end of the 17th century, Carrickfergus Castle became the focus of the most definitive and iconic military event in Irish history.

But this battle wasn't just about who ruled Ireland, it was about who would rule England.

When the Catholic king James II was chased out of England, he set about amassing a huge army, first in France and then in Ireland.

The intention was to win back his crown.

Because in England, a new Protestant king was on the throne... (INDISTINCT CHANTING) And even today his name is a rallying cry in tensions across Ulster's religious divide.

When we think of all the famous kings of England, William III doesn't usually feature very highly.

But in Ireland, William III or William of Orange is an icon and a hero to the Protestant population.

William invaded England in 1688 from Holland, aiming to put an end to the Catholic revival led by his father-in-law, James II.

And Carrickfergus Castle would be absolutely pivotal.

William's conquest of England was a relatively bloodless affair.

But in Ireland, after centuries of sectarian slaughter, nothing was ever bloodless.

Carrickfergus Castle was now held by forces loyal to James II, who were called Jacobites.

In 1688, the castle's defenses were state-of-the-art.

It had been revamped to include artillery, with gun ports and embrasures for cannon installed around the walls.

Soon, they would be put to the test.

The next summer, the castle was under attack.

When the Irish Jacobite garrison heard William's forces were on the way, they burned homes in the town and dragged Protestant hostages into the castle.

William's general, Frederick Schomberg, attacked with 10,000 men and forced the Irish garrison to surrender.

But it's what happened next that showed the depth of hatred between Catholic and Protestant populations.

Outside the walls, local Protestants waited.

The cowardly acts of the Jacobite garrison would soon be revenged.

An eyewitness wrote that as the garrison left the castle the local people, "Stripped most part of the women "and forced a great many arms from the men.

"And that Schomberg was forced to ride in among them "with his pistol in his hand to stop the Irish from being murdered."

But there was more bloodshed to follow.

A year later, in 1690, William realized James II was planning to use Ireland as a launch pad for an invasion of England.

He decided to cut him off.

He was at the head of a 36,000- man army of English, Scottish and Dutch Protestants.

William was heading for a showdown with James II, who was himself at the head of a massive Catholic army.

The future of Britain and the freedom of Ireland was on the line.

After landing his forces at Carrickfergus, William marched south to meet James II and his followers, known as Jacobites.

And the two armies came together here to fight one of the most important battles in Irish history, the Battle of the Boyne.

William's troops were professional soldiers, well-trained and equipped with the latest artillery and muskets.

The Jacobite forces, on the other hand, were mainly Irish peasants armed with little more than scythes and hay forks.

The outcome was inevitable.

Outmatched and outfought by William's well-drilled army, the Jacobite forces scattered in disarray.

(EXPLOSION) And to the disgust of his Irish supporters, James II turned and fled to France.

It was a stunning victory for William, which would ensure the Protestant ascendency over Ulster.

And it's still celebrated to this day, every year on July 12th.

(MARCHING BAND PLAYING) Just over a hundred years after the Battle of the Boyne, the Orange Order was founded.

When they march through towns like Carrickfergus today, they're remembering William III's victory on one of Ireland's bloodiest days.

The triumph of William of Orange established a Protestant ruling class in Ulster.

Over the next century or so, Carrickfergus was overtaken by Belfast as the political center of Northern Ireland.

In 1928, the British War Department transferred Carrickfergus Castle to civilian control after 750 years of continuous military occupation.

There's no better symbol of the turbulent history between Britain and Ireland.

(GRUNTING) From the Norman Conquest to the Tudor plantation, the Cromwellian war and the triumph of William of Orange, today, Carrickfergus is remembered as a Great British castle that stands proudly as a monument to the victories and the victims alike.