[1][page needed] Being the eldest daughter of the King of Hungary and Poland who had no sons, Catherine was a much wanted bride.

When she was only four years old, she was betrothed to Louis, a younger son of King Charles V of France and future Duke of Orléans.

Her father made a set of concessions to the Polish noblemen in exchange for recognizing Catherine (or one of her sisters) as sovereign of Poland after his death.

Her father also planned to leave her his claim to the Crown of Naples and the County of Provence, which were then held by his ailing and childless cousin Joanna I.

[2] Her younger sister Mary, who was betrothed to her fiancé, became heir presumptive and eventually monarch of Hungary.