MALVOLIO: ‘Besides, you waste the treasure of your time with a foolish knight – ‘
SIR ANDREW: That’s me, I warrant you.
MALVOLIO: ‘One Sir Andrew.’
SIR ANDREW: I knew ’twas I, for many do call me fool.

– William Shakespeare

Twelfth Night, Act 2, Scene 5. Malvolio calls Sir Andrew a “foolish knight.” And Sir Andrew seems to be proud that he guesses Malvolio is talking about him.