Pope leo x's jubilee indulgence was meant to raise funds to:

Pope Leo x's jubilee indulgence was meant to raise funds to rebuild St. Peter's Basilica in Rome. This church was built by the emperor Constantine. St. Peter's Basilica in Rome was in desperate need of repair. The church needed more space for pilgrims and for priests to officiate around the high altar.

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).