Turkey and Russia both straddle Europe and Asia. Ukraine is the largest country entirely within Europe. The people of Belarus, Russia and Ukraine all claim the powerful medieval state of Kievan Rus' as part of their cultural heritage. This was a loose federation of East Slavic tribes, under a family which ruled for 21 generations. The state disintegrated after a Mongol invasion, and its successor principalities paid tribute to the Golden Horde. Between the 13th and 20th century, the area has been contested between powers including Lithuania, Poland, the Ottoman Empire, Austria-Hungary and Russia. Kievan Rus' is part of the founding identity of Russia too. The 2014 revolution was driven by whether relations were deepened to the left with Europe, or to the right with Russia.