Months before Vladimir Putin launched a full-scale military invasion of Ukraine, he published an essay on the Kremlin website called "On The Historical Unity of Russia and Ukraine." In it, he suggested that Ukrainians don't really have their own identity — and that they never have. Historian Serhii Plokhii says that couldn't be further from the truth. The histories of the two countries are deeply intertwined, but Ukrainian identity is unique. In this episode NPR's Throughline explores that identity: how it formed, it's relationship to Russia, and how it helps us understand what's happening now.