Gregory VII., Hildebrand, born in Tuscany; bred up as a monk in a life of severe austerity, he became sensible of the formidable evils tending to the corruption of the clergy, due to their dependence on the Emperor for investiture into their benefices, and he set himself with all his might to denounce the usurpation and prohibit the practice, to the extent of one day ex-communicating certain bishop who had submitted to the royal claim and those who had invested them; his conduct roused the Emperor, Henry IV., who went the length of deposing him, upon which the Pope retaliated with a threat of excommunication; it ended in the final submission of Henry at Canossa (q.v.); the terms of submission imposed were intolerable, and Henry broke them, elected a Pope of his own, entered Rome, was crowned by him, and besieged Gregory in San Angelo, from which Guiscard delivered him to retire to Salerno, where he died, 1035; he was a great man and a good Pope.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Gregory III. * Gregory IX., Ugolino