Abbas Mirza
Crown Prince Abbas Mirza of Persia, at the instigation of the Russian Empire, invaded Western Armenia and the areas surrounding the Iranian province of Azerbaijan. On September 10, 1821, the Iranian forces marched out of Tabriz towards the border. On September 16, Iranian forces crossed the border at Gürbulak and them stormed the Bayezid Fortress in November 1821, securing Persian supply routes. The governor of Baghdad's invasion of Persia is defeated by Mohammed Ali Mirza who then besieges Baghdad, his untimely death ends the siege. Meanwhile, Abbas Mirza marched into eastern Anatolia with 30,000 troops and met an Ottoman army of 50,000 at the Battle of Erzurum. Abbas Mirza scored a crushing defeat over the Ottomans despite being severely outnumbered and his army suffering from a cholera epidemic.