Now here’s a surprise! The Cheikho CSCO edition came out in 1912. The PO edition came out starting in 1910 (PO5) 1911 (PO7) 1912 (PO8) and 1915 (PO11). Even on the face of it, that means that the first fascicle — which covers the time of Jesus — was only just before the CSCO text.
But looking at the CSCO introduction, the first sentence tells us that the text was set up in type five years earlier — that is, in 1907. Unspecified delays prevented printing until 1912. So in fact the two editions are quite independent, as regards half of the text.
The introduction goes on by telling us that he must have known Greek letters, as well as Syriac and Arabic; that he must be a Melchite, since he acknowledges the council of Chalcedon and refers approvingly to the see of Rome.
Agapius alludes to the date when he was writing (p. 334 of the CSCO edition), as being the eighth month of 330 A.H. (i.e. AD 942). Eutychius must precede him slightly, as the latter died at the end of Ragab, 328 AH (11th May 940 AD). Both authors are mentioned by the Moslem author `Ali Ibn Husain al-Mas`udi (X, 957).
The CSCO text was published in Lebanon, and naturally made use of eastern copies. For the first part of the work, it used a Bodleian Nicol. manuscript. Cheikho knows of two more at Sinai, which he could not use. He was able to use two mss in Beirut, both owned by the St. Joseph Catholic University. The first, which he calls A, was bought at Emesa (Homs) and dates from the 16th century. The second (B) was written in Lebanon in 1818. A third ms. (C) was found in the seminary of the Syrian Patriarch at Scharfa, dating from 1662 AD. A fourth written in 1882 he had seen in a monastery at Luaize in Lebanon, but this was already lost when he wrote. A fifth manuscript — he doesn’t say if he used it — was in the Greek Patriarchal library of the Holy Sepulchre in Jerusalem.
All these, he says, are pretty much identical to the Oxford ms. and all end in the middle of the same sentence, apart from the Scharfa ms. which ends on fol. 104. He used A and B, with bits of C.
For the second part, he had a photographic copy of the unique Florence manuscript. He also made use of al-Makin from Paris ms. Arab. 294 — the one which I was sold a wretched microfilm of — and printed the excerpts from Agapius from it at the end of his edition (which, drat it, I didn’t notice).