Where the Qedarenes ended up

Thomas "the Presbyter", whose brother was one Shimʿon doorkeeper of Qedar upon mount Mardîn, gets most attention by historians of Islam: for his witness AG 945 then 947. Thomas didn't think he was recording Islam; he thought he was recording "the Tayyaye". (He was overall a particularly bad chronicler, but never mind that for now.) AG 945, the Tayyaye of Mahmet routed the Romans; 947, having ravaged both Syria and "Persia" (=al-ʿIraq), they ascended Mardîn. This hilltop had two sites at the time: Qedar and "Bnôtô", as west-Syrians pronounce those vowels.

It turns out the Syrians remembered (1) why the Tayyaye hit those places and (2) whither they all went. Michael the Syrian 11.5:

At that time, the Taiyaye invaded the Persian countries; they went up on the mountain of Marde, near Reshʿayna, and killed many monks in the convent called Qedar and in that of the Bnôtô, because they had been told that they were the spies of the Persians. The few monks who survived [the Bnôtô] came to the wilderness to the west of the river called Baliha: they found a spring there so built a convent near it which they called the convent of Beit Rîshyar, after the archimandrite of the convent of the Bnôtô. (That had been so called because of the "daughters", that is to say the eggs of a bird that Jacob had found, who was the first to inaugurate the convent.)

For their part, those of the monks of the convent of Qedar who survived came to the edge of Callinicum [= al-Raqqa], near a temple where was a column which the Empress Theodora had built. They extended this place and dwelt there; it was [then] called the convent of the Column.

Yes, that is the Empress Theodora. Michael goes on a longer digression next, so long that he must defend his ramble afterward. As for Callinicum, the Muslims today say it was under their jurisdiction already by AD 640ish. Note that Thomas doesn't know where the monks went.

- which I read as, won't tell where they are planning to move. If so Thomas assembled his "chronicle" at Reshʿayna, from whatever documents either Mardîn monks had brought from up there. At a guess Thomas felt he owed to his late brother to epitomise the local records, which Thomas did in a hurry, because the surviving monks were planning to emigrate, being under the Tayyayes' suspicions in Reshʿayna.

NEIGHBOURHOOD WATCH 4 MARCH: As for "spies of the Persians" we may assume that Yazdegerd was preparing Nisibin for opportunism or at least for defence.