By the early 12th century, the German archbishoprics of Bremen and Magdeburg sought the conversion to Christianity of neighboring pagan West Slavs through peaceful means. During the preparation of the Second Crusade to the Holy Land, a papal bull was issued supporting a crusade against these Slavs. The Slavic leader Niklot preemptively invaded Wagria in June 1147, leading to the march of the crusaders later that summer. They achieved an ostensible forced baptism of Slavs at Dobin but were repulsed from Demmin. Another crusading army marched on the already Christian city of Szczecin (Stettin), whereupon the crusaders dispersed upon arrival (see below).