- When the Kingdom of Hungary's army was annihilated by the Mongols at the battle of Mohi, only the castle of Esztergom stood in their way to invade Europe. Batu, the grandson of Genghis Khan, reaches the walls of Esztergom with his invincible army. The castle's defenders led by Eusebius, the canon of Esztergom, and a Sp…