Schaff, Philip. "The Didache and the Catacombs." The Oldest Church Manual Called the Teaching of the Twelve Apostles. Second Edition, Revised and Enlarged. New York: Funk & Wagnalls, 1886, 36-41.
The topic of baptism takes Schaff to a consideration of art in the Roman Catacombs (Schaff 1886, 36). Paintings found there represent people being baptized in a river, with the baptizer on dry land. The person being baptized is unclothed, which suggests immersion (Schaff 1886, 37). Schaff presents pictures of these catacomb paintints along with descriptions of the paitings. By the time of Constantine baptistries were regularly built near churches, bringing the river baptisms to an end (Schaff 1886, 41).