On 28 August 1553, the Sultan started from Istanbul for a new military expedition to Iran. This was his twelfth mili-taiyexpedition. He was quite an aged man, 59 years old. The Sultan arrived in Erzurum via Konya and Diyarbakir and from there he advanced in Kars direction. Sending an insulting letter to the Shah as his father Sultan Selim, had Previously done, challenged him to a fight. But none of these treats yielded a result, the Iranian army once again did not appear on the scene. The Turkish army proceeded in the directions of Karabag and Nahcivan areas. Although the Sultan’s army reached as far as Nahcivan, Shah Tahmasp and his army where always freeing away. Under these conditions, the army was set free to enter and completely destroy the city. The Sultan believed that doing that much damage was good enough and decided to return.
When the army reached Erzurum on its way back, the Sultan received an appeal from the Shah for an armistice. It was accepted on condition that peace was realized and the enmity between the two countries was terminated. The Sultan’s plans were to spend the winter of 1554-1555 in Amasya and to continue the operations against Iran in the spring. Shah’s envoy arrived in Amasya with new proposals, precious gifts and a letter to the Sultan. A Peace treaty, was made when Shah gave a word of assurance for friendship (1555). According to these treaty Azerbaijan and its capital Tebriz, the eastern part of Anatolia and the Arabian Iraq were being annexed to the Ottoman State.
This first treaty concluded with Iran was in effect until the year 1576. Through the peace of Amasya, the fights of the Ottomans and Iran which stretched over half a century came to an end. During the military expeditions of the Magnificent, no Iranian army had the courage to get involved in a decisive battle with the Ottoman armies. Therefore, the military expeditions were no more than invasions. The Iranians however, after the withdrawal of the Ottoman army continued their attacks to the Eastern Anatolia. The Ottoman State during this war,secured contact with the Turkish States in the Central Asia forming an alliance with them and extending assistance.