Ottoman–Persian War (1821–23)

The Ottoman-Qajar War was fought between the Ottoman Empire and Qajar Empire from 1821 to 1823.

Reasons
Tensions between the two empires had been rising due to the Ottoman Empire's harboring of rebellious tribesmen from Iranian Azerbaijan. Although secretly, the Russian Empire was attempting to put pressure on the Ottoman Empire, which was at war with the Greeks, who were receiving arms from Russia.

War
Crown Prince Abbas Mirza of Persia, at the instigation of the Russian Empire, invades Kurdistan and the areas surrounding Iranian Azerbaijan. 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 marches into eastern Anatolia with 30,000 troops and meets an Ottoman army of 50,000 at the Battle of Erzurum. Abbas Mirza wins the battle of Erzurum, despite a cholera epidemic.

Result
Peace was not concluded until the Treaty of Erzurum two years later; both sides recognized the previous borders, with no territorial changes. Also included in the treaty, was the guaranteed access for Persian pilgrims to holy sites within the Ottoman Empire.