Answer:
There were totally 266 popes since the beginning.
The one that declared Crusades was Urban II.
Step-by-step explanation:
The first Pope was of course Saint Peter and there were altogether 265 Popes after him, and the current is Pope Francis I.
Urban II declared Crusades in 1095 after the council in Clermont in 1095. The Crusades started after Byzantine emperor asked for help in the fight against the Seljuk Turks, but became something totally different that he expected.