Adalgar a Benedictine monk of Corby, and the companion of Rembertus, or Rheinbertus, whom he succeeded, in 888, in the archiepiscopal chair of Hamburg and Bremen. The archbishop of Cologne claimed supremacy over Cologne, and Pope Formosus cited Adalgar to appear at Rome to prove his rights to the archbishopric, but he refused both to attend in person and to send a deputy. The investigation was intrusted to the archbishop of Mayence, who decided against Adalgar, who was placed among the lowest bishops. The archbishopric was restored by a bull of Sergius III, A.D. 905. Adalgar established a seminary of priests for the propagation of the Gospel in the North, and died May 9, 909, after holding the see for nineteen years.