The conversion of Spanish Muslims failed partly from under-resourced evangelization

Evidence

Writers later in the sixteenth century, trying to find an explanation for the ultimate failure of the Spanish Christian attempt to turn Muslims into Christians, besides condemning the perversity of the stubborn Muslims, also often laid some blame on deficiencies in the initial evangelization campaigns, but there is no reason to suppose that the ecclesiastical authorities did not take their new task seriously, although we must bear in mind the limited means available to them. — L. P. Harvey, Muslims in Spain, 1500 to 1614, 367