Ukraine

Ukraine is a country.

Pre-Kievan Rus
none

Kievan Rus' (900-1100 CE)
Kievan Rus' is founded since 966 CE (?), and was collapsed into countries in the 12th century, then the Mongolian invasion by Genghis Khan attacked Kievan Rus' later then beyond until it reaches Poland and Hungary where Mongolian Empire collapsed. Later becomes part of Poland-Lithuanian Commonwealth.

Poland-Lithuanian Rule (1300-1600 CE)
Since the rise of Poland-Lithuania, it had been conquered by them, including some of Ukraine. Russia controls the rest after the Ottomans abandoned the Crimean area. Soon, the Partition of Poland, Russia has Ukraine.

20th Century
After WWI, the Ukrainians were trying to get independence, but it later got destroyed by the Soviets, and during WWII, the Nazi Germany occupies some of Ukraine, including Romania occupying some of Ukraine's south. Then got destroyed and becomes part of USSR. When the last leader of USSR resigned, Ukraine becomes a country.

Euromaidan and Russia (2013-2014 CE)
The Euromaidan has been risen by small amount of people, soon to become a mass of protests. When it happened, Crimea declared their independence, an independence referrum has happened in Crimea. With the Russians won, it became part of Russia, but some think it's illegal. Donetsk becomes People's Republic of Donetsk as few pro-Russians declared independence.

Ethan
I think Ukraine would become a large war later on, with USA and allies on the Ukrainian side while Russia and its allies side with the Russian side.