The crusade is a feature of medieval Christian civilisation with a decidedly contemporary resonance. The crusades are also highly relevant to current academic debates about the relationship between core and periphery in later medieval western European culture. As early as the Second Crusade in the 1140s an attempt was made to synchronise multiple crusade expeditions on three general fronts: in the Middle East, in Spain and in north-eastern Europe. The theological bases and the popular reception of the various formulations of the crusade indulgence are both hotly debated by historians. Western pilgrimage to the East had already been picking up in the eleventh century, and the success of the First Crusade made possible a veritable pilgrimage boom. In terms of facilitating expressions of religious devotion, the most noticeable effect of the crusades was the Latin control of Jerusalem and the Holy Places between 1099 and the Muslim reconquest under Saladin in 1187.