Saint Altfrid (or Altfrid of Hildesheim) (died 15 August 874) was a leading figure in Germany in the ninth century. A Benedictine monk, he became Bishop of Hildesheim, and founded Essen Abbey. He was also a close royal adviser to the East Frankish King Louis the German.
He is a Roman Catholic saint. His feast day is celebrated on 15 August, the feast of the Assumption of the Virgin Mary, but also in Essen and Hildesheim on 16 August.