In the Elizabethan great chain of being, it was "minerals" that were at the lowest rung of human society, since it was believed that these were the foundations of plant life and nothing more.
Abraham Lincoln is my answer
Several reasons.
Saw this crusade as a blessing from God.
Christians would stop fighting themselves.
Christians that would fight would go to heaven or be right with God.
To take back the holy lands, from the Muslims would be a righteous cause.
