The Teaching of Jacob, is a 7th-century GreekChristianpolemical tract set in Carthage in 634 but written in Palestine sometime between 634 and 640. It supposedly records a weeks-long discussion ending on July 13, 634, among Jews who have been forcibly baptized by order of the emperor. One of them, Jacob, has come to believe sincerely in Christianity; he instructs the rest about why they should also sincerely embrace their new faith. Halfway through, a Jewish merchant named Justus arrives and challenges Jacob to a debate. In the end, all of the participants are convinced to embrace Christianity, and Jacob and Justus return east. In addition to several partial Greek manuscripts, the text survives in Latin, Arabic, Ethiopic and Slavonic translations. The text provides one of the earliest external accounts of Islam, presenting a significantly different Islamic historiography than found in traditional Islamic texts. It also shows Jacob comparing the Byzantine Empire to the fourth beast of the prophecy of Daniel from Judeo-Christian eschatology. Although not unfamiliar imagery, it is part of a series of Byzantine literature, from the early stages of the Islamic religion, of trying to reconcile Islam with the apocalyptic vision. Further examples of this are contained in the pseudo-Athanasian's Quaestiones ad Antiochum ducem, and the Quaestiones et responsiones attributed to Anastasius of Sinai. It records a prophet in Arabia during the birth time of Islamic tradition proclaiming the advent of a Jewish Messiah. The document contradicts the notion in Islamic tradition that the prophet was dead at the time of the conquest of Palestine but agrees with some traditions of other peoples of the time.
"What is significant here is the possibility that Jews and Arabs seem to be allied together during the time of the conquest of Palestine and even for a short time after"
"This document is plausibly one of the most archaic elements of the Islamic tradition, its agreement with the earliest external accounts of the origins of Islam is highly significant"
"To be sure, the picture given in the Doctrina Iacobi seems garbled, and many of its details disagree with the traditional account.... Yet one could hardly expect a Byzantine source from this early and turbulent period to get all the detailsright. Even later, most Byzantine sources displayed gross misunderstanding of matters Islamic, just as Muslim sources generally did of matters Byzantine." - Colin Wells.
