Appanage

The appanage was an important concept in the history of France during the Middle Ages. According to the customary law, when a king died, his oldest son became the next king. If a king wanted to give some land to a younger son, he sometimes also created an appanage, which was one way to keep a civil war. That could happen if two or more sons wanted to fight each other to be the next king.

The younger son controlled the appanage as a duke and ruled almost like a king except he could not sell the land. The ruler of an appanage could give it to his sons and grandsons, but that branch of the family would eventually run out of sons, and the land would go back to the king.