The Shocking History Of Treason In Britain - From Kings To Guy Fawkes

Heritage Horizons
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3 Video Views·Aug 30, 2026
Step inside the National Archives to uncover the real stories behind Britain's most notorious treason trials, from Guy Fawkes to Anne Boleyn and King Charles I.
In this video, we explore the fascinating history of treason in Britain, tracing its roots back to the 1352 Treason Act and examining how its definition shaped the
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Remember, remember the 5th of November. Gunpowder, treason and plot.
I see no reason why gunpowder treason should ever be forgot.
Over the centuries, the word's been linked with some of the most audacious attacks on the establishment.
If it fails, it would usually lead to the most gruesome of death penalties.
The story of treason centres around one document from the 14th century
and it's on display here at the National Archives.
Some of the most famous names in British history have been convicted traitors.
William Wallace, Anne Boleyn, some we might recognise as noble rebels,
others as cheated of their reputation by false accusations, driven home by the weight of the state.
The National Archives at Kew is home to some of Britain's most ancient and most spectacular documents.
There's over a thousand years of history in there, all housed and cared for.
I'm here today to take a look at their brand new exhibition, all about treason.
Every single one of these stories revolves around this 670 year old Act of Parliament.
The 1352 Treason Act.
It's set out to define what constituted treason.
It was enacted by Edward III, but why was it set out in law?
Curator Ewan Roger is on hand to give me some answers.
So this is the beginning of the story of treason here in this exhibition.
And why does Edward III bring this act in now?
Is this in response to a crisis that he's facing or is this dealing with some longer term issues?
So treason's always been part of the national story, the relationship between the crown and the nobles.
But under Edward I it starts to be used in a really targeted way to crush the king's enemies,
to crush the rebels in Scotland and Wales.
And then under Edward II, treason develops even further and starts being used by factions at court against one another,
with arbitrary charges of treason being used against rival factions.
We think about treason laws about protecting the king, but is this actually limiting what he can call treason?
Very much so. This is quite a narrow definition of treason that they go for in 1352.
And it's in response to Parliament saying, please tell us what treason is defined as.
So there are five key clauses that are still in law today.
The first and most important of these is compassing or imagining the death of the king or the senior male royals.
And that's basically a plotting to kill the king. That's the classic treason that we might think of.
The second is violating the queen or the senior female royals.
And the third and fourth clauses, which are quite linked, are levying war or adhering to the king's enemies.
So that's very much taking battle against the crown.
And the fifth of these, which is perhaps more unusual, is it makes it treasonous to kill the chancellor, the treasurer or the royal justices,
but only while they're doing their official business, not just when they're walking down the street.
It's probably quite a narrow definition of treason.
I mean, I think some of the most famous treason cases we can think of might not have fallen under this act.
So does it evolve and develop as it lives and breathes? As you say, it's still in law today.
Yeah, there are a couple of key things that are left out of the definition in 1352.
But also we have a key clause in this document which regulates how treason will be redefined or added to over time.
So it states in this document that if anything happens in the future which might be deemed to be treasonous,
that's not to be decided by the king alone, but by the king in Parliament.
So it very much centres the definition of treason in the future in Parliament, in that institution.
Defining treason then was always as much about limiting the monarch's power to call something treason
as it was about protecting the crown.
In 1440, England was on the brink of chaos.
The Hundred Years' War with France was drawing to a disastrous close
and there were dynastic struggles beginning at home.
The king, Henry VI, was in his late teens, unmarried and childless.
His heir was his last remaining uncle, Humphrey, Duke of Gloucester.
In an early glimpse of the paranoia that would drag his kingdom into civil war,
Henry began to look at his uncle with deepening suspicion.
His first move was against his uncle's wife, Eleanor Cobham,
and there are some documents that show exactly how Henry set out to accuse Eleanor of treason.
What is she accused of in 1440? What leads her into court?
She's accused of having two men, Roger Bolingbroke and Thomas Southall, forecast a horoscope for the king
to find out when he will die.
So she's not plotting his death as such, but just trying to find out when it will happen.
We're still 200 years from the height of the witch trials,
but I think what we can see here is the harnessing of that fear and uncertainty to deliver a political aim.
Eleanor's sex is weaponised against her husband.
Effectively, she's accused of witchcraft here.
Yeah, so it's really interesting because she's put on trial as such in two ways,
by a spiritual court and by a secular court.
The inner secular court is a bit of a problem because there's no precedent at this point
for how to put a noblewoman on trial.
Magna Carta had set out in 1215 the rules for trying a nobleman for treason,
but it gave no thought to how a noblewoman might be prosecuted.
To get around this, Eleanor was put on trial in church courts for witchcraft
and in the secular courts as an associate of two men accused of treason.
It was a legal fudge to deliver what the crown wanted.
They're accused of using necromancy and astronomy and magic
to summon demons of the air and of the earth to produce this horoscope
and find out when the king will die.
What she's accused of is not in the 1352 Treason Act,
but they frame it as such by using what's called constructive treasons.
So the royal justices are arguing in this instance that by casting this horoscope
and, crucially as well, telling people about this horoscope,
telling people when the king will die,
the people of the country will withdraw their love from the crown, from the king,
and he will become sad and melancholic as a result
and will therefore die sooner than he originally had done.
Eleanor's case saw an effort to correct that omission in Magna Carta.
Now, noblewomen could be tried for treason by a panel of their peers,
albeit their male peers.
This loophole meant that Eleanor escaped the ultimate punishment in the secular courts.
Although she was found guilty in a spiritual trial,
that didn't carry the death penalty.
Eleanor was forced to divorce Humphrey and to perform public penance,
to undertake a walk of shame through London streets on three separate days.
She was then imprisoned for the rest of her life.
This case also highlights the problems that medieval England had with powerful women.
They couldn't be tolerated behaving in any way other than that was expected of them,
but they also couldn't be killed.
Eleanor Cobham's treason trial changed the rules,
though it would take almost a century more and a desperate, ruthless king
to actually take the step of executing a noblewoman.
Henry VIII ripped at the fabric of England
as he clawed to secure a male heir to succeed him.
The king wanted to set aside his wife and remarry,
but ending a royal marriage would need permission from the Pope in Rome.
Here, Henry hit a roadblock.
To explore how Henry manipulated the law to get around that obstacle,
I'm meeting with curator Dan Gosling.
Dan, why do we end up with this fabulous-looking act of supremacy?
So in the 1530s, Henry VIII was getting increasingly frustrated with the Pope.
The Pope's head of the Catholic Church.
Henry wanted to get an annulment from his first wife, Catherine of Aragon,
and the Pope wasn't letting him because he said you can't do it on religious grounds.
So the extreme reaction, the final reaction from Henry was
he broke from the Catholic Church, the Church of Rome,
and he declares himself supreme head of the Church of England.
By 1535, Henry had most of what he wanted.
He'd annulled his marriage to Catherine of Aragon,
was head of the Church of England, married to Anne Boleyn.
He had a daughter, Elizabeth, but still craved a son.
As he waited impatiently, the political fallout of his choices was becoming dangerous.
One of Henry's closest friends and one of the most respected men in England,
Sir Thomas More, was about to go on trial,
and not for something he'd done, but for something he'd refused to say.
This document here is about him trying his friend Thomas More for treason.
What does Thomas do?
He refused to swear the oath of succession.
Now the oath of succession was basically saying
I confirm that Anne Boleyn is the true queen
and any heirs by Anne and Henry are the true heirs of the kingdom.
Thomas More wasn't refuting that, but he refused to swear the oath of succession
because the preamble to it denied the authority of the Pope in England,
and then that's what he's put on trial for,
and that's what he's executed for because he says during his trial
the act of Parliament is like a sword with two edges
because if I go one way, if he follows the king,
it's to the discredit of his soul, if he's going against God.
If he goes the other way, what he believes in is to the discredit of his body.
Sir Thomas More was executed on 6th July 1535.
To some, he's a martyred saint.
To others, he's a vicious religious zealot.
Either way, he was a victim of a collapsing treason system.
The extent of Henry's willingness to use treason laws to get what he wanted
can be seen in another document.
If it was shocking to see Henry turn on one of his best friends,
it almost defied belief to see him turn the laws he used to marry Anne Boleyn
against that queen.
Famously, not just his friends who fell foul of Henry's expanding treason laws,
it's also his wife, because next to Thomas More's trial documents
you have the trial documents of Anne Boleyn.
The woman who precipitated all of this is now falling foul.
So Anne Boleyn, she was tried and executed for treason,
that was her official charge in 1536,
and her accusation was adultery and then incest with her brother as well,
but they said that was a treasonous act because she was the Queen of England
and those actions put the king's life at risk.
One, in the record it says that Henry VIII got so sad it diminished his health,
so it was a risk to his life and they said that was a treasonous act,
but they also said that what Anne Boleyn was doing,
she was using her feminine wiles to attract these suitors.
The original treason act had made it an offence to assault the queen
and other royal women, but what if it was the queen
who was accused of adultery?
Now, Henry was calling anything he didn't like,
and maybe even things that he'd made up,
acts of treason that required the death penalty.
The suitors, the alleged adulterers of Anne Boleyn,
they're all bang to rights on the 1352 treason act
because they are accused of violating the king's wife as a king's consort,
but for Anne it's a little bit different because there's nothing in the 1352 act
that says that a queen committing adultery against the king is a treasonous act,
so they have to add in these things about her actions
of putting the king's life at risk.
Anne was beheaded on 19th May 1536 by a swordsman brought from the continent
by Henry VIII specifically to do the deed.
It was a small mercy from an increasingly frenzied man.
His teenage son, Edward VI, and his advisers saw the danger
in what his father had done when he became king in 1547.
After Henry VIII's death, the first parliament that Edward VI reigned,
he enacts a statute repealing all of Henry VIII's treason laws,
so basically saying he's gone a bit too far,
his father went a bit too far with treason laws,
watering down the importance of it,
and the statute says we repeal all of those and going back to the 1352 statute.
One of the most notorious English cases of treason
occurred in 1605 with the Gunpowder Plot,
a Catholic scheme to blow up Protestant King James and his parliament,
but before the plot could succeed,
someone gave the game away as one of these documents reveals.
This pretty unassuming-looking letter kind of changes the course of the Gunpowder Plot.
What is it and what does it say?
So this small letter here, this is the so-called Monteagle letter,
so it was delivered to Lord Monteagle, that's why it's called that,
late October 1605, and it's anonymous, it's an anonymous hand, it's unsigned,
but basically what it says is,
if I were you I wouldn't attend the state opening parliament on 5th November,
it doesn't give any reason why, it just says,
go to the country, see what happens from there,
and if you burn this letter after receiving it,
then everything will be fine, no one will be in trouble.
Lord Monteagle doesn't burn it,
he's a sort of prominent Catholic nobleman in England,
he knows what happens to Catholic noblemen
if they conceal any sort of attempted treason,
so he takes it immediately to the king,
and his council shows it to them,
and that's what prompts the thorough searches of the House of Parliament.
There's still debate today about who wrote this letter.
It could have been Monteagle himself,
as a way to expose a plot he disapproved of,
even though he was a Catholic.
It may have been one of the plotters,
seeking to save Lord Monteagle,
who perhaps feared it was a test of his loyalty to the government,
and handed it over, rather than burning it wherever it came from.
This piece of paper is the reason the gunpowder plot was uncovered.
Fawkes was arrested in the undercroft beneath the Houses of Parliament.
He began by admitting very little,
even using false names to avoid revealing his true identity.
He's interrogated seven or eight times in those first few weeks,
and so important is it to the king and council
to find out exactly how big this plot is.
James I actually authorises torture.
Which results in a document we have at the end here,
which is kind of a declaration by Guy Fawkes,
but it's really a confession.
As the torture intensifies, Guy Fawkes' resolve is ground away,
until he reveals the names of his accomplices.
As those who are still alive are arrested,
they begin to corroborate each other's stories.
This was precisely what the 1352 Treason Act had been created for.
Although we would suggest today that you should be a little bit wary
of any kind of a confession that's extracted under torture.
Absolutely, and even at the time they realised that torture
was only to be used in the most exceptional circumstances,
and James in his sort of authorisation does say
only if the normal procedures aren't working
then the gentler tortures may be used,
and he uses that exact thing, gentler tortures.
So yeah, they knew that morally and legally it was a bit iffy,
so they only wanted to use it in exceptional circumstances,
which this absolutely was.
I'm not sure I fancy any of the gentler tortures.
No.
But is this ultimately, the 1352 Act, working exactly as it should?
Exposing a plot against the King, finding out all the details of it
and dealing with those who moved against it?
Yep, and they had absolutely no trouble
prosecuting the surviving gunpowder plotters.
Sir Robert Catesby died in the shootout made for November,
but the surviving plotters were tried in January 1606,
and it was a standard treason trial,
and no one had no trouble fixing them with treason,
saying, like, this wasn't just treason against the King,
it was treason against the whole state and government.
There's more to that Remember, Remember, the 5th of November poem.
It continues,
Guy Fawkes and his companions did the scheme contrive
To blow the King and Parliament all up alive
Three score barrels laid below
To prove old England's overthrow
But by God's providence him they catch
With a dark lantern lighting a match
Guy Fawkes is synonymous with the gunpowder plot,
but he wasn't even the main conspirator.
So why is he the person that we remember today?
These documents help us to explain that.
We remember him because he's the man that the government had.
He's the one that they could try, that they could make an example of,
and that they could publicly execute.
Mind you, he even managed to cheat that at the end.
He was due to be hanged, drawn and quartered,
but as he climbed the steps to the gallows,
he jumped and snapped his own neck,
skipping the worst of that punishment.
Treason and its trial really went smoothly.
Just 20 years after the gunpowder plot,
treason trials took a drastic turn.
James's son came to the throne in 1625 as Charles I.
His efforts to rule without involving Parliament
created friction that flared into civil war.
In 1649, in a shocking move,
Charles himself was accused of treason.
The question was how to try a king for treason.
Charles refused to recognise the authority of the court or enter a plea.
The court refused to back down,
insisting that Magna Carta had made it clear
that even the king wasn't above the laws of England.
More than four centuries after its creation,
that principle was about to be put to the ultimate test.
Dan, what are we looking at here? What is this book?
So this is the manuscript journal of the trial of Charles I.
So he was tried in January 1649,
and then shortly afterwards they made this journal.
How is the treason law being used to accuse a king of treason?
Does that require some bending?
A little bit. They're on legally shaky grounds,
so they can't prosecute in the normal way through treason
because the 1352 Treason Act is a common law statute,
so it had to be tried in King's Bench.
And the king was sort of the fount of that justice.
You can't try a king in King's Bench.
So the commons get around this
by creating a high court of justice to try Charles Stuart.
And then they treat it, after they've established that court,
they treat it exactly like a normal treason trial.
So what do they actually accuse Charles of?
So the sentencing actually accuses him of treason.
It says, Charles Stuart, you are found guilty of levying war
against the parliament and people of the realm.
So it's treason against the kingdom rather than treason against the king,
and that's how they can justify trying the king for treason,
because they argue that by this point
treason doesn't just protect the person, the monarch,
it's the entire government, it's the entire realm.
Magna Carta had settled in 1215 that no-one was above the law,
not even the king.
That theory was put to the ultimate test.
On 30 January 1649, Charles Stuart, one-time king of England,
was beheaded for treason,
committed against a country that he felt he ruled by God's authority.
Parliament had condemned the king.
In 1352, the Treason Act had sought to protect the crown,
but also to take away some of its power.
Almost 300 years later, parliament asserted with deadly force
that treason law protected not one man or woman who sat on a throne,
but the entire nation.
The shield had now become a sword.
