Turkey-Russia Relations in the Twenty-First Century: Deepening Cooperation and Heightening Competition amid Systemic TurbulenTurkey and Russia are two of the most significant powerhouses in Eurasia. The foreign policies of two countries directly impact the regional dynamics in Black Sea, Central Asia, Middle East, Eastern Europe, and the Balkan regions. The changes in the bilateral relations between the two countries go well beyond the Black Sea region. In the past, the Russian Empire played a significant role in the collapse of the Ottoman Empire, and Turkey took part in