A Historical Look at Crucifixion John Dominic Crossan is professor emeritus of biblical studies at DePaul University in Chicago. A native of Ireland, and ordained as a priest in the United States, he left the priesthood in 1969. Crossan is a founding member of the Jesus Seminar, a group of scholars who meet to determine the authenticity of Jesus' sayings in the Gospels. Crossan wrote the books Jesus: A Revolutionary Biography, The Historical Jesus and Who Killed Jesus? Exposing the Roots of Anti-Semitism in the Gospel Story of The Death of Jesus.