Recently, I worked through the ITunes U lecture series on the Historical Jesus, as presented by Thomas Sheehan of Stanford. One of Sheehan’s assertions was that pre-gospel Christianity was comprised of a northern school, centered around Galilee, which focused on the sayings of Jesus and a southern, Jerusalem school, which emphasized Jesus’ works and deeds, and that the synoptic gospels were ultimately a redaction of the writings of these two schools. I believe he located the gospel of Thomas and the Q-source within the northern tradition. He did not reference any specific scholars who have developed this two-school notion—does anyone have any information as to the evidence that supports this depiction of early Christianity?