Eusebius of Emesa

I hear that Ishoʿdad cited one Eusebius of Emesa, Arabically Ḥimṣ. I think this town was Arabic-speaking already by Eusebius' AD fourth-century / AG seventh-century. Although: what dialect?

Eusebius himself spurned Arabic. Eusebius didn't approve Greek, either; he was a man Jerome would have approved, a Hebrew enjoyer. To that end Eusebius made a strong play for Biblical "Syriac", as he called it (ho Suros). "Syria" in his days expanded into Emesa on past Damascus. To narrow this down: from the quotations he makes therefrom (against the Greek), our scholars tend to see ho Suros as an ancestor to Peshitta. That's the Edessene language, not the Palaestinian language.

To narrow this in time: the Peshitta like the Vulgate is famously post-Masoretic. I conclude that Syriac had already displaced more-Palaestinian Aramaics at Ḥimṣ, among Christians, by the 300s / 600s.