Latin-speaking Muslims in medieval Africa

In the Middle Ages as today, Christians and Jews regularly called God "Allah" when speaking Arabic, just as Muslims did . It is perhaps not as well known that the converse was often also true: from a very early period, North African Muslims called God "Deus" when speaking Latin. This can clearly be seen on the 8th century Umayyad coins of Tunisia and Spain, which include statements such as:

• Non deus nisi Deus solus - There is no god but God alone (لا إله إلا الله)
• Deus magnus omnium creator - God is great, the creator of all things (الله أكبر خالق كل شيء)

I had always assumed it more or less stopped there, as Latin-speaking Muslims shifted to Arabic. But in the towns of southern Tunisia, the former Bilad ul-Jarid, Latin was still being spoken well into the 12th century. In his recent book La langue berbère au Maghreb médiéval (p. 313), Mohamed Meouak uncovers a short recorded example of spoken African Latin from between these two periods, which otherwise seems to have escaped notice so far.

The 11th-century Ibadi history of Abu Zakariyya al-Warjlani, he gives a brief biography of the Rustamid governor Abu Ubayda Abd al-Hamid al-Jannawni (d. 826), who lived in the Nafusa Mountains of northwestern Libya. Before assuming his position, this future governor swore an oath:

Bi-llaahi (by God) in Arabic, and bar diyuu in town-language (بالحضرية), and abiikyush in Berber, I shall entrust the Muslims' affairs only to a person who says: "I am only a weak being, I am only a weak being."

In al-Shammakhi's later retelling, the languages are named as Arabic, Ajami, and Berber (بلغة العرب وبلغة العجم وبلغة البربر). As Mohamed Meouak correctly though hesitantly notes, diyuu must be Deo; he leaves bar uninterpreted, but it is equally clearly Latin per, making the expression an exact translation of Arabic bi-llaahi. The Berber form is probably somewhat miscopied, but seems to include the medieval Berber word for God, Yuc / Yakuc.

The earliest Romance text is the Old French part of the Oaths of Strasbourg, made in 842 and opening Pro Deo amur... "for the love of God". The Ibadi phrase recorded above curiously echoes this, although it predates it by several decades.