Altfrid was a ninth-century Benedictine monk and the Bishop of Hildesheim who served as a prominent political advisor to King Louis the German. Born around 800, likely within the Saxon nobility, he rose through the monastic ranks at Corvey Abbey before his consecration in 851. He played a significant role in the diplomatic negotiations of the East Frankish kingdom, helping to shape the Treaty of Meerssen. Beyond his political influence, he was an active founder of several religious institutions, most notably Essen Abbey.