So here's a summary:
Born 1825-1849, died on or before Jan 1, 1900.
European head of state, but much of Europe has been eliminated.
Here's what's left, as far as I can figure out:
Switzerland, Austria, Hungary, Romania (or the 19th-century equivalents of those nations).
Edit: a better way to put it... here's what has been eliminated:
British Isles
France
BeNeLux
German 2nd Reich states
Anything bordering Mediterranean Sea
Scandinavia
Russia
So in addition to what's listed above, Portugal is still on the table, and some far east nations near Russia. Maybe a few more?