His election, which occurred after the historical and dark abdication of Celestine V, was opposed by French Cardinals and by the powerful Colonna Family.
V letu 1265 je bil za "capitulum" v Anagniju rimske province dominikanskega reda dodeljen Tomaž Akvinski kot regent mojster , s čimer se spreminja obstoječo "studium conventuale" v rimskem samostanu Santa Sabina v prvi red "studium provinciale" kot novost študija filozofija ("studia philosophiae").