The whole idea of the royal succession was for the throne to pass from the King to his adult, prepared, son. That’s the pattern that makes the “The King is dead, long live the King” thing work. But in English and Scottish and British history, that didn’t always happen. Sometimes there wasn’t an adult son ready to take the throne. Sometimes (gasp!) the throne went to a woman! And sometimes (double gasp!), it went to a child. Throughout Medieval times, when the King needed to rule and a strong King meant a strong country, a child on the throne was a bit of a problem. It was right there in the Bible: “Woe to thee, O land, when thy king is a child.”

It was not automatically a full disaster. But it was certainly less than ideal. 

It had taken Henry VIII nearly 30 years of his reign to have a son, so by the time Edward was born, the King was in his final decade. Henry’s health was failing by the end of 1546. So he did everything he could to help smooth the way for his son to take and keep the throne. Although young, Edward was a determined and dedicated reformer and his reign saw significant reforms and the beginning of the use of the term “Protestant.” Edward’s second Book of Common prayer provided a model for worship that would be used for 400 years. He was beginning to write in his journal about his frustration with those who didn’t follow his religious laws—it’s likely that if he had lived longer, his persecution of Catholics would have increased. But Edward was one of the few child Kings who did not grow to adulthood and rule on his own.

One of the interesting things about the reign of Richard II was that he had one of his best royal moments while still in his minority. Although just 14 years old, Richard responded decisively. He met the rebels at Mile End and agreed to some of their demands. The rebels grew restive and the King’s men responded, pulling Tyler off his horse and killing him. Despite the rebels’ outcries, Richard shouted that he was their true captain and led them away from the scene. It was not the end of outbreaks of rebellion, but Richard had shown his potential as a leader and exercised authority in the defeat, capture, and execution of the rebels. Ironically, Richard’s success with the Peasant’s Revolt turned out to contribute to his downfall. It seemed to fuel Richard’s belief in his absolute power as King—and he started to exercise it.

If it’s bad to have a king who’s a child, imagine the potential disaster if the King is an infant. Especially in the midst of a huge war with France. There’s a moment at the end of Shakespeare’s Henry V, after the “band of brothers” speech and the glories of Agincourt and the humor of King Henry and Princess Katherine where the Chorus comes back on stage and rips the thrill of victory right out from under us. Henry V’s victories were followed shortly by his early death.
Henry the Sixth, in infant bands crown’d King
Of France and England, did this King succeed;
Whose state so many had the managing,
That they lost France and made his England bleed.

Of course, England wasn’t the only country with child Kings. The Stuarts saw a series of Kings named James take the throne as children. In 1406, James I was 12 and in captivity when he became King. James II became King at age 6 after his father was assassinated. The exact birth of James III is disputed, but he certainly was no older than 10 when he became King. James IV became King of Scotland at age 15 after his father died in battle. James V was only 17 months old when he became King after his father’s death in battle. And James VI was only 13 months old when he became King. So from 1406 to 1567, the incoming King was a young boy. There was, of course, one exception. Still a child, but not a boy. The exception is, of course, Mary Queen of Scots. 

So having a child on the throne may have been as bad as prop

History shows us what's possible.