 As well as being an intimate and ally of the popes, especially Sylvester II, Gregory also served as "praefectus navalis" of Holy Roman Emperors Otto I and Otto II.However, on 6 February 1001, he was named "Head of the Republic" by the Romans for leading the revolt against Otto III and expelling the Crescentii.In 1002, the latter returned to power and he had to renounce his title.