In 1683, Rye House in Hertfordshire was at the centre of a plot to assassinate King Charles II and his brother, James, Duke of York.

The Rye House Plot was masterminded by a group of conspirators including two residents of Watford: the Earl of Essex, of Cassiobury House, and the Duke of Monmouth, of Moor Park.

The Gunpowder Plot, when Catholics attempted to blow up both King and Parliament, had heightened many people’s distrust of Catholics. Charles was known to have Catholic sympathies, and James had converted to Catholicism in 1673.

The only solution to prevent England’s return to Catholicism, the plotters argued, was to kill both Charles and James.

The Rye House Plot was ultimately unsuccessful, many of the plotters were executed, and people felt renewed sympathy for the King and his brother.

The Plot is part of a long history, stretching back hundreds of years, of attempted assassination attempts on royalty.

James I of Scotland became king in 1406 after living as Henry V’s prisoner for nearly 19 years. He became a cruel and ruthless king and made many enemies during his reign.

James spent Christmas of 1436 at Blackfriars Monastery with his Queen. The monastery had its own tennis courts, James’s favourite sport, and he continued to stay there into the new year.

On the evening of February 20, 1437, James was resting with his wife and her ladies when they heard raised voices coming from outside and realised he was in danger.

James asked the women to keep the door guarded as best they could while he searched for a means of escape.

Finding it impossible to break the leaded windows, James instead grabbed an iron tong from the fireplace and began to pull up the floorboards. Underneath was a drain for the privy, and he climbed inside and pulled the floorboards back into place.

A few days earlier, he could have followed the drain and escaped into the monastery grounds, but he had had the opening blocked just days before, as he kept losing his tennis balls down the drain.

A group of men burst into the room and, after a thorough search, found their King hiding in the sewer. They stabbed James to death.

Due to the actions of James’s enraged wife, Joan, all of the assassins were captured and executed.

Assassination attempts were not always due to subjects rebelling against their kings and queens. Sometimes, royalty turned on each other.

The Babington Plot of 1586 was a plan to assassinate the Protestant Elizabeth I and put her Catholic cousin, Mary, Queen of Scots, on the English throne.

Mary was the focal point of many plots to restore England to Catholicism. She became so dangerous that Elizabeth felt she had no choice but to imprison her – for 19 years.

Sir Francis Walsingham, Secretary of State, and William Cecil, the Queen’s chief advisor, realised that unruly Catholics would lack a figurehead if Mary was no longer around. If Mary was implicated in a plot to assassinate Elizabeth, she could be legally executed.

The Babington Plot began when John Ballard, a Jesuit priest, recruited Anthony Babington in a plan to rescue the Scottish Queen and assassinate Elizabeth.

Walsingham’s double agent, Gilbert Gifford, acted as a courier, intercepting all letters sent to and from Mary and passing them on to Walsingham. The Secretary of State had the letters decoded and thus discovered Babington and Ballard’s plot.

The final piece of the evidence came when Mary wrote a letter confirming her support for the murder of Elizabeth if it meant she would be released from imprisonment and England returned to the Catholic church.

The conspirators were arrested and sentenced to death.

Mary was put on trial and convicted of treason. On February 8, 1587, she was beheaded in front of 300 witnesses.

Although many would-be assassins have turned on their monarchs for religious beliefs or the hope of social improvement, there is also a history of people with mental health problems attempting to kill members of the royal family.

On August 2, 1786, Margaret Nicholson approached King George II as he alighted from a carriage at St James’s Palace. She presented him with a petition (actually a blank piece of paper) and when he reached to take it she lunged at him with a dessert knife.

She was quickly brought under control and George was reported as saying, ‘The poor creature is mad; do not hurt her, she has not hurt me.’

During a search of Margaret’s lodgings authorities discovered a series of delusional letters in which she claimed to be the rightful heir to the throne. She also claimed to be the mother of Lords Mansfield and Loughborough, both of whom were older than she was.

She was certified insane and committed to Bethlem Royal Hospital, where she died 42 years later.

George II’s descendent, Queen Victoria, was also targeted for assassination - no less than seven times.

The first attempt came in June, 1840, just two years after her coronation.

She was riding in a carriage down Constitution Hill with her husband, Albert, when 18-year-old Edward Oxford drew two pistols and fired twice at the Queen. Both shots missed.

Later that same day, Victoria and Albert returned to Hyde Park, escorted by a large number of guards, and greeted the cheering crowds. It was only when she reached her bedroom at Buckingham Palace that the 21-year-old monarch burst into tears.

Oxford was seized by witnesses and charged with high treason. He was found insane by doctors and committed to an asylum, where he later claimed that his only motive for the attack was notoriety.