The Estonian Crusade refers to a series of military campaigns in the early 13th century aimed at converting the pagan peoples of Estonia to Christianity. Initiated by the Teutonic Knights and supported by the Danish and Swedish forces, these campaigns were part of the broader Northern Crusades that sought to expand Christian influence in the Baltic region. The crusade began around 1208 and continued until the mid-1220s, resulting in the establishment of Christian rule in parts of Estonia. The campaigns faced resistance from local tribes, leading to significant battles and the eventual integration of the region into the Christian world.