After the Turks seized the City of World's Desires in 1453, a crusade was called by the Pope. As was common of the later crusades, few answered the call and even fewer participated. Pius himself attempted to lead the crusade himself but died.
My question is what if a much more sizeable force was assembled for the Pope to use against the infidels and the ensuing invasion was actually successful in at least securing some cities in Greece if not expelling the Turks from Europe completely?