
“At [Nero's] hands [Peter] received the crown of martyrdom being nailed to the cross with his head towards the ground and his feet raised on high, asserting that he was unworthy to be crucified in the same manner as his Lord.”
A quo et affixus cruci, martyrio coronatus est, capite ad terram verso, et in sublime pedibus elevatis: asserens se indignum qui sic crucifigeretur ut Dominus suus.
Source: De Viris Illustribus, Chapter 1