LOUIS XIII. (1601-1643), king of France, was the son of Henry IV. and of Marie de' Medici. He became king on his father's assassination in 1610; but his mother at once seized the full powers of regent. She determined to reverse the policy of her husband and to bring France into alliance with Spain and the Austrian house, upon which power Henry had been meditating an attack at the time of his death. Two marriages were designed to cement this alliance. Louis was to marry Anne of Austria, daughter of the Spanish king, Philip III., and the Spanish prince, afterwards Philip IV., himself was to marry the Princess Elizabeth, the king's sister. Notwithstanding the opposition of the Protestants and nobles of France, the queen carried through her purpose and the marriages were concluded in 1615. The next years were full of civil war and political intrigue, during which the queen relied upon the Marshal d'Ancre. Louis XIII. was a backward boy, and his education had been much neglected. We have the fullest details of his private life, and yet his character remains something of a mystery. He was fond of field sports and seemed to acquiesce in his mother's occupation of power and in the rule of her favourites. But throughout his life he concealed his purposes even from his closest friends; sometimes it seems as if he were hardly conscious of them himself. In 1617 he was much attached to Charles d'Albert, sieur de Luynes; and with his help he arrested Marshal d'Ancre, and on his resistance had him assassinated. From this time to her death the relation between the king and his mother was one of concealed or open hostility. The article on FRANCE must be consulted for the intricate events of the following years.