The Gospel of Barnabas was translated into English from an Italian manuscript and published in 1907. It was also translated into Arabic very soon after its appearance in English, a project driven by Rashid Rida. This led to its being widely circulated, and becoming a point of contention between some Muslims and Christians as to whether it was a more authentic gospel than the canonical gospels found in the New Testament.
There is very extensive evidence that it is the product of a convert from Christianity to Islam from sometime during the second millennium. This evidence includes inaccuracies over geography and historical anachronisms. It also disagrees at points with Qur’anic teaching.The exact origin of the document is a matter of debate. The items listed below suggest a range of possibilities for its origins lying in Italy, Spain, Cyprus, or Istanbul.
Ragg, L. & L. (tr.) The Gospel of Barnabas (Oxford: Clarendon Press, 1907) [this translation is frequently reprinted without the Raggs’ critical introduction].
Ayoub, Mahmoud ‘Muslim Views of Christianity: some modern examples’ in Islamochristiana 10 (1984), 49-70; reprinted in Ayoub, A Muslim View of Christianity, ed. Irfan Omar (Maryknoll, N.Y.: Orbis Books, 2007) [An example of a Muslim author’s rejection of the authenticity of the Gospel of Barnabas].
Koningsveld, P.S. v ‘The Islamic Image of Paul and the Origin of the Gospel of Barnabas’ in Jerusalem Studies in Arabic and Islam 20 (1996), 200-228 [suggests an Italian original, but written in Istanbul].
Leirvik, Oddbjørn: ‘History as a Literary Weapon: The Gospel of Barnabas in Muslim-Christian Polemics’ in Studia Theologica – Nordic Journal of Theology, 56:1 (2002), 4-26
Pulcini, T. ‘In the Shadow of Mount Carmel: the Collapse of the “Latin East” and the Origins of the Gospel of Barnabas’ in Islam and Christian-Muslim Relations 12 (2001), 191-209 [argues for it originating from a monk on Cyprus who converted to Islam].
Ryad, U. Islamic Reformism and Christianity: a critical reading of the works of Muhammad Rashid Rida and his associates (1898-1935) (Leiden: Brill, 2009)
Slomp, J. ‘The Gospel in Dispute’ in Islamochristiana 4 (1978), 67-111.
—— ‘The “Gospel of Barnabas” in Recent Research’ in Islamochristiana 23 (1997), 81-109.
Sox, D. The Gospel of Barnabas (London: George Allen and Unwin, 1984).
Wiegers, G. ‘Muhammad as Messiah: A Comparison of the Polemical Works of Juan Alonso with the Gospel of Barnabas’ in Bibliotheca Orientalis (1995), 245-291 [argues for Italian origin].