Ado of Vienne (died 16 December 874) was archbishop of Vienne in Lotharingia from 850 until his death and is venerated as a saint. He belonged to a prominent Frankish family and spent much his early adulthood in Italy. Several of his letters are extant and reveal their writer as an energetic man of wide sympathies and considerable influence. Ado's principal works are a martyrology, and a...