Saint Vicelinus (also Vicelin, German: Vizelin; 1086 – December 12, 1154) was a German bishop of Oldenburg who was considered the apostle of Holstein. Orphaned at an early age, Vicelinus received his primary education at Hemeln, his birthplace. He left secretly for Paderborn, where he enjoyed the home and instructions of Hartmann, and soon surpassed his companions and assisted in the management of the cathedral school.