Thanks to Stephen C. Carlson, I learned a few days ago that volume 1 of Bar Hebraeus Chronicon Ecclesiasticum was online in PDF form at Google Books here. Unfortunately this 1872 book is kept behind their “US-only” firewall, although it is out of copyright everywhere in the world.
I’ve placed an ILL for volume 2, which I will scan if it arrives and place online at Archive.org.
The work itself consists of short entries on figures in the Syriac church from the beginning down to the author’s own time. A parallel Latin translation is provided. The first volume is the important people in the West Syriac church; the second is their opposite numbers in the East Syriac church. I don’t know what volume 3 is, tho!