At some point in the 21st century, we can expect that Prince William will be crowned King William V. As the oldest son of the Prince of Wales, the Prince, who turns 40 next year, has been assumed likely to one day be King from the moment of his birth.

The same is not true of the four previous King Williams who have, in the past, ruled England. None of the four grew up expecting to be King. Three of them were not even born here.

Long before 1066, William the Conqueror (1066-1087) had established a formidable reputation as an exciting and effective military leader as Duke of Normandy. Born in 1027 or 1028, William had inherited the Dukedom at the age of seven, but on reaching adulthood he quickly consolidated his hold over a duchy, fighting off a major attempt to conquer Normandy by King Henry I of France.

All of which was good practice for his eventual conquest of England which came after he defeated the last Saxon King, Harold II at the Battle of Hastings. William successfully crushed rebellions in Exeter, York and elsewhere and despite the betrayal of his half-brother, Odo, held onto Normandy too. His last years saw the creation of the famous Domesday Book survey. Overweight, ageing and in poor health, he died after falling off his horse while fighting to defend the city of Mantes near Normandy in 1087.

On William’s death, the Conqueror’s oldest son, Robert Curthose, inherited the duchy of Normandy while his next son, William II (1087-1100) known as ‘Rufus’ because of his ruddy complexion, took over England. Rufus was not a strong or popular leader. In 1100, he was shot and killed by an arrow while hunting in the New Forest. Some said it was an accident but it was almost certainly murder. With his older brother Robert away fighting in the First Crusade, Rufus’s younger brother, Henry, and his friends left the fallen king’s corpse by the road as they hastily galloped off to Winchester so that Henry could claim the throne for himself.

Nearly 600 years later, another foreign-born warrior called William claimed the throne of England. This time it was the Dutch Prince William of Orange, a figure seen as a potential hero by many English Protestants, horrified by the Catholic sympathies of King James II and who personally invited him to intervene. The year was 1688 and England was in a state of religious turmoil. William was married to James’s daughter, Mary, also a Protestant, who it was decided would rule jointly with her husband. The couple set sail as part of a huge fleet of 463 ships including 53 warships and 40,000 men, a force three times the size of the Spanish Armada a century before. They arrived in Torbay. What became known as ‘the Glorious Revolution’ was actually a bloodless coup and only bloodless because James II initially chose not to fight but to flee. William III (1689-1702) ruled jointly with Mary II until her death from smallpox aged 32 in 1694. In an echo of an earlier King William, he died after falling from his horse when it tripped over a mole-hill in Richmond Park.

62 years later, the future King William IV (1830-37) was born in what was then known as Buckingham House and later Buckingham Palace. As the third son of George III, William had little expectation of becoming King himself but with none of George III’s 15 children very good at producing legitimate heirs (William had ten illegitimate children by a mistress himself), he eventually succeeded his brother, George IV, as King at the age of 64.

A failed naval officer, William was never a popular figure and was nicknamed ‘Sailor Billy,’ ‘Silly Billy’ or ‘Old Melon Head.’ His head was indeed an unusual shape. A bystander threw a rock at it but he was protected by some padding he wore to help ensure hats could stay on his peculiarly-shaped cranium. On his death, he was succeeded by a much more successful monarch: his 18-year-old niece, Queen Victoria.