Actually, Shards, you've got the historian in me going. History is a big part of the appeal OOB has for me. So I checked some things out.
First of all, it's the birthday of the independent Republic of Estonia, not Estonia itself. According to Wikipedia, "The territory of Estonia has been inhabited since at least 9000 BC." For much of that time, it was ruled by Germans, Danes, Swedes, and Russians.
However, "Estonians experienced a national awakening in 19th century. On 24 February 1918 independence was declared and later secured through [the Estonian]
War of Independence."
Now
there is an idea for another scenario, eh? If OOB ever expands to that era, perhaps. Or maybe a semi-fictional version using units from 20 years later.

- Estonian_War_of_Independence,_map.JPG (115.01 KiB) Viewed 1236 times