Arthur’s reference is the Crusader

The Crusades were a series of religious wars initiated, supported, and sometimes directed by the Latin Church in the medieval period. The best known of these Crusades are those to the Holy Land in the period between 1095 and 1291 that were intended to recover Jerusalem and its surrounding area from Islamic rule. Concurrent military activities in the Iberian Peninsula against the Moors and in northern Europe against pagan West Slavic, Baltic and Finnic peoples also became known as crusades.

Through the 15th century, other church-sanctioned crusades were fought against heretical Christian sects, against the Byzantine and Ottoman empires, to combat paganism and heresy, and for political reasons. Unsanctioned by the church, Popular Crusades of ordinary citizens were also frequent. Beginning with the First Crusade which resulted in the recovery of Jerusalem in 1099, dozens of Crusades were fought, providing a focal point of European history for centuries.