Stephen Weinstein wrote, in response to the original query, that:

The original records were written in Russian, in an alphabet that has
been obsolete for almost a century, except possibly in Bulgaria (after
the Bolshevik Revolution, the Soviet Union adopted a simplified
alphabet instead of using the one that had been used under the Czars).

I respectfully submit that this information is not quite true. It's not
the ALPHABET that is now "obsolete", but simply that there are a few
spelling differences. Not all that many, and once you get used to them
they're not much problem. Bulgaria also reformed their spelling,
probably around the same time. I know both languages: the alphabet is
nearly identical, with a couple of letters used in Russian that are not
used in Bulgarian, and some phonetic differences.

Anyone who can read the present-day Russian (or Bulgarian) should be
able to make things out in the old spelling, after a little introduction
to "what changed" - English Wikipedia has a nice article on this:
https://en.wikipedia.org/wiki/Russian_spelling_reforms

Martha Schecter Forsyth
Newton, MA

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