Who commissioned Death of St. Peter Martyr by Giorgio Vasari and why did they commission it?

Answer :

Comissioned by Pope Paul.

WHY:

The picture shows St. Peter's martyrdom. According to an ancient and well-known account, when Peter was sentenced to death in Rome, he requested that he be crucified upside down because he did not feel that a man was worthy of being slain in the same manner as Jesus Christ.