Don Quixote was the main character of a book and a play, The Man of La Mancha.
He was eccentric, to be polite, fantasizing of great feats of heroism and bravery, all to rescue the fair Dulcinea. He ran around the countryside with his companion, Sancho, and is the origin of the term "tilting at windmills".
A spanish "soldier" - his looks depend on whose depiction.
One made him tall, thin and lanky - another made him short, squat, pretty fat.
He's a retired country gentleman in his fifties, lives in an unnamed section of La Mancha with his niece and a housekeeper. He has become obsessed with books of chivalry, and believes their every word to be true, despite the fact that many of the events in them are clearly impossible. Quixano eventually appears to other people to have lost his mind from little sleep and food and because of so much reading.
His most famous "act of chivalry" is fighting windmills.