Ukraine is very much in the news lately because of its disputed election. Much of the commentary on Ukraine's ethnic divisions concentrates on the Uniate Catholic ethnic Ukrainians of the western regions and the Orthodox Christian ethnic Russians of the eastern regions. But that doesn't tell the whole story.
Ukraine has a Muslim population of about two million. Most of these are Crimean Tatars.
Historically, Crimea was predominately Muslim. During the 1850s, Russia began its conquest of this region, leading to the Crimean War.
But the most tragic chapter of Crimea's history would come in 1944, when Stalin deported 200,000 Tatars from Crimea, accusing the entire population of being Nazi collaborators. This was part of a much larger campaign of ethnic cleansing and genocide by Stalin. Besides the Crimean Tatars, he also ordered mass deportations of Volga Germans and seven (predominately Muslim) nationalities of the Caucusus - including the Chechens; there's a reason they don't want Russia ruling over them anymore. Historians estimate that at least 1.5 million people were deported by Stalin during and after World War Two. See commentary such as Counting Stalin's victims 50 years on, The 20th century's worst crime goes unpunished, and Stalin's legacy.
After the collapse of the Soviet Union, Crimean Tatars who were living elsewhere in the former Soviet lands were allowed to return, and about 250,000 have done so to Crimea itself, where they face many difficulties and tense relations with the ethnic Russians who now predominate in Crimea. They continue to remember their history.