Rabbi Avigdor Hacohen was the pupil of R. Simha of Speyer (who flourished about 1220), but he knew also R. Joel HaLevi of Bonn (who flourished about 1175). Avigdor lived in Vienna, and from there administered the religious affairs of the Jewish population of Austria.
Rabbi Avigdor Hacohen was a rabbi who studied under Rabbi Simha of Speyer and also learned from Rabbi Joel HaLevi of Bonn. He resided in Vienna and oversaw the religious life of the Austrian Jewish population.