What do you do, when you find that the mediaeval Greeks carelessly forgot to preserve a copy of some patristic text in which you are interested? Well, you have a couple of choices.
Firstly you can go and search manuscript libraries and see if you can find it. This option is rarely exercised, since dealing with many Greek libraries is only just preferable to torture.
Your other alternative is to see if anyone translated it into something else, before it was lost.
This happened a lot. Back in the 5th century, the Armenians sent off an expedition to Edessa, got a whole load of Syriac books, and translated these into Classical Armenian. They also set up a monastery in Jerusalem, which translated books and sent them back to the old country. As a result we have works by Irenaeus and Eusebius extant in no other language.
Old Slavonic is another language group that came into contact with the Greek world during the Dark Ages. The language was spoken by Old Slavs (of course). Once these had been taught literacy, they too acquired Greek literature.
I’ve found in Harnack’s Geschichte der altchristlichen Litteratur bis Eusebius, Theil I, halfte 2 — which I can’t find online — a list of ante-Nicene patristic authors whose works are extant in Old Slavonic. The list is more than a century old, but I think it would be interesting to look at, for those of us who know almost nothing about that language group. More in my next post!