They became legendary for their frequent displays of gallantry.
Explanation:
The concept of "gallantry" encompasses many different qualities. A gallant behaviour includes being polite and courteous towards women, being brave in battle, performing heroic deeds, and behaving morally towards others. Don Quixote particularly respects this behaviour, and he believes that Spanish knights became legendary because of these acts. He tries to replicate them, particularly in his mental dealings with "Dulcinea."
