Mongol invasion of Europe

From the 1220s to the 1240s, the Mongols conquered the Turkic states of Volga Bulgaria, Cumania and Iranian state of Alania, and various principalities in Eastern Europe. Following this, they began their invasion into Central Europe by launching a two-pronged invasion of then-fragmented Poland, culminating in the Battle of Legnica (April 9, 1241), and the Kingdom of Hungary, culminating in the Battle of Mohi (April 11, 1241).

Source: Wikipedia — Mongol invasion of Europe (CC BY-SA 4.0)