During the eleventh and twelfth centuries, Latin Christendom — the area that employed the Latin rite and looked to Rome for ecclesiastical and spiritual leadership — had grown phenomenally. Instrumental in the success of Latin Christians' campaigns of conquest were the heavily-armed and mailed horseman — the knight (miles) — and the crossbow (arbalista); physically symbolic of their newly-implanted domination was the castle. An especial boost to the power of the papacy and the cohesion of Latin Christendom was the rise, around the beginning of the twelfth century, of international religious orders which looked to Rome for guidance and direction. Confronting expansionist Latin Christendom were two types of opponent. In Northern Europe, the pagan territories into which Western knights and peasants advanced belonged to polytheists – Slavs ('Wends') or Baltic races like the Prussians, Livonians and Estonians.