Became Pope in 1534 and died in 1549. Generally acknowledged as the first reforming Pope. Promoted Cardinals on real ability, for example Contarini, Reginald Pole, Sadoleno and Caraffa.
Commissioned report of 1536 called Concilium de Emendenda Ecclesia identifying the problems within the Church.
Encouraged the revival of religious orders such as Capuchins, Theatines and most importantly the Jesuits.
Probably his greatest achievement was calling a general council in the form of the Council of Trent. The first session of the Council was in 1545-1548. The council was instrumental in the reform of the catholic church and many Popes had feared calling a general council after the conciliarism movement of the 15th Century.
A great reformer but not completely free of the vices of previous Popes – he fathered four illegitimate children and installed two of his grandsons as Cardinals.