Charles VI, king of France
Charles VI (1368-1422) king of France (1380-1422) came to the throne at the age of 12 on the death of his father, and immediately found himself beset by the problems caused by four uncles, all royal, competing for power. He was short of funds, the kingdom was full of unrest; however when he was twenty he managed, with the help of his brother, to wrest power from his squabbling uncles and rule in his own right with the help of a group of relatively low-birth advisers, previously appointed by his father.
He then began suffering bouts of madness, his uncles returned to power, and he spent the rest of his life controlled by others, hardly understanding what was happening. In 1420 he was “persuaded” to sign the Treaty of Troyes with Henry V of England, granting Henry regency of France until Charles’ death and the succession of Henry and his heirs to the French throne.
One daughter, Isabella, became the second wife of Richard II of England (when only seven!), and another, Catherine, married Henry V (as part of the Treaty of Troyes) and become the mother of Henry VI, whose periodic madness, inherited from his grandfather, would be a major contributing factor in the events that led to the Wars of the Roses.