The death of an heir is always a tragedy. But when you’ve been so focused on your eldest that the younger son isn’t kept as a proper back up it can make things even more difficult.

Philip of France was born in August 1116. His father, King Louis VI (also known as “Louis the Fat” for obvious reasons) was on his second marriage. He had first married Lucienne de Rochefort but after three years he had repudiated her and had the marriage annulled. His second wife, Philip’s mother Adelaide of Maurienne, had fallen pregnant a few months after the wedding. Over the years she would give Louis eight children; seven sons (of which one died in infancy) and one daughter.

As the first born of this hefty brood of healthy males Philip was named after his paternal grandfather. He is believed to have been his father’s favourite child (not always a guarantee for the eldest, there are plenty of instances in history where the father preferred the spare), at least in childhood.

But a growing son who is groomed to be king will inevitably want to get some regal experience before his time. Following French tradition Louis had Philip crowned as his co-king in 1129 when the boy was thirteen. This tradition was used to show the direct line of inheritance and reduce the risk of a younger sibling stepping forward on the father’s death to claim the crown and start a civil war.

Unfortunately it could also go to a prince’s head. After he was crowned Philip appears to have gone through a teenage rebellious phase. He reportedly refused to listen to his father scolding him and rejected any attempts to discipline him. As a prince his household would have included other young noblemen his age and it’s possible that this group egged him on to reject his father’s discipline and attempts to mould him into a future king. Louis certainly wouldn’t be the first King, or the last, to have problems with his eldest son.

Having survived the worst perils of childhood there was no doubt every expectation that Philip would go on to greater things. Like many young men the idea of travel appealed to him, and like many young men of his time he talked about visiting the Holy Land, perhaps as a pilgrimage or even a crusade. He was still too young but no doubt in a few years he would be able to persuade his father to let him go, if only to stop him causing trouble at home.

One day in October 1131 the fifteen year old prince was riding along with a group of friends when his horse stumbled and threw him off. The story says that a black pig ran in front of the party and the horse tripped on it. But there were plenty of obstacles on the unclean streets that could cause a nasty accident.

Whether they were travelling back home or just out for a ride, the party were probably going at some speed. Philip was thrown off so viciously that he broke several bones when he landed on the ground, which almost certainly included his neck or spine. He was knocked out instantly and although he was brought home as quickly as possible, he died the next day without regaining consciousness.

His “spare” had been his younger brother Louis. But Philip had been so healthy and so full of promise that Louis had never been intended for kingship. Instead he had been raised among a community of monks, with a monk as a tutor and the glory of a committed religious life dinned into his head on a daily basis. This unprepossessing boy was plucked out of religious contemplation by his father and rushed back to court to be crowned as co-king.

This prince would become King Louis VII. As the husband of Eleanor of Aquitaine he proved to be a less than adequate lover. One wonders if Eleanor would have had a better time of things if she had been married to Philip. Would Aquitaine have ever been part of England’s Angevin empire? But Louis did do one thing for his dead brother. He remembered Philip’s desire to visit the Holy Land. In time he would declare and lead the Second Crusade to honour his brother’s wish. It would not go well.

Last months Almost King was Balthasar Charles, Prince of Asturias.