The massive world chronicle of Michael the Syrian, composed during the crusader period, survives in a single manuscript in a box in Aleppo. The box has two locks, each held by a senior figure in two different churches. Access is difficult.
Making things worse is that J.-B. Chabot in the early 20th century somehow got access, and somehow surreptiously made a copy. Quite how you can surreptiously make a copy of something the size of two telephone directories I don’t know, but he did. He published it with French translation — we may all be grateful for this, since many Syriac books were destroyed in WW1 — but the owners still remember, and are still angry with him.
The opening portion of the chronicle is lost. But an Armenian version preserves the preface, which Langlois’ edition of 1868 (French only) makes available online.
Few people seem to know much about the Armenian versions of Michael the Syrian. But from Michael E. Stone, The Armenian texts of Epiphanius of Salamis De mensuris et ponderibus, CSCO 583, Subsidia 105 (2000) — an excellent text, fromwhat little I can see in the preview — on p.25, I learn this:
Vardan Arewelc’i translated Michael’s Chronicle into Armenian in the year 1246, with the assistance of the Syrian priest Ishox and at the request of the Armenian Catholicos Constantine. See N. Bogharian, Armenian Writers, 296.
He also refers to an article by F. Haase, Die armenischen Rezensionen des syrischen Chronik Michael des Grossen, Oriens Christianus NS 5 (1915), 60-82, 211-284. That ought to be online somewhere! Apparently this indicates that more than one version exists or existed. He also indicates that material from Moses of Chorene contaminates the translation of Vardan Arewelc’i.
Another link indicates another article: Andrea Schmidt, Die zweifache armenische Rezension der syrischen Chronik Michaels des Grossen, Le Museon 109 (1996), p.299-319. This seems to be inaccessible to proles like you and I, but searching around the web reveals that this has been mentioned to me before here in a useful set of comments. Andrea Schmidt has a home page here, with a long bibliography. I do wish that some of it was online.
I also find D. Weltecke’s article in English on the chronicle here in PDF form. This useful introduction tells me that there are two versions, published in Jerusalem in 1870 and 1871 (but not what the titles etc are). A book in German by Dorothea Weltecke, Die “Beschreibung der Zeiten” von Mōr Michael dem Grossen (1126-1199) is online in preview here, where on p.7 we read more about the history of these versions, and a review of previous research.
So … a rather inconclusive result. I’ve gained a little impression of the subject, but not much. I was hoping to locate an Armenian text online, although not with much hope.