The story
From the character Sancho Panza from Miguel de Cervantes's novel Don Quixote.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A person perceived as both foolish and wise and who takes claims at face value, and who is usually the companion of a more important or powerful person whom they idolize beyond reason. Full definition →
From the character Sancho Panza from Miguel de Cervantes's novel Don Quixote.
Etymology from Wiktionary, CC BY-SA 4.0.