The First Crusade may have been launched in 1095, but warfare between Muslims and Christians dates back to the 630s. The Byzantine Empire had been fighting for its life ever since the Arabs emerged out of Arabia. The Christians in Spain had been at war with the Muslims since 711. Charlemagne invaded Spain to fight the Muslims.
There were some atrocities committed during the Crusades (killings of Jews in the Rhineland, massacre of inhabitants in Jerusalem when it was captured) but they pale in comparison to the slaughters committed by those seeking to expand the territories ruled by Islam.
But his base also forgot that it was the same Christians who ended both slavery and Jim Crow laws.