<human>:  Did the first Duke of Valentinois play a key role in the Hundred Years' War?
<bot>: No, the first Duke of Valentinois did not play a key role in the Hundred Years' War. The Hundred Years' War was a conflict between England and France from 1337-1453. Cesare Borgia, the son of Pope Alexander VI, was the first Duke of Valentinois. Cesare Borgia was born in 1475, so the first Duke of Valentinois was born before.