The discord in Iran had allowed its enemies, the Uzbek khans in the east and the Ottoman Empire in the west, to seize territory. The Ottomans were at the height of their power during the reign of Suleiman the Magnificent. They launched four invasions of Iran between 1533 and 1553. Since the Ottoman army possessed overwhelming numerical superiority, Tahmasp avoided pitched battle with them and resorted to alternative tactics.
In 1534, Suleiman invaded Iran with a force numbering 200,000 men and 300 pieces of artillery. Tahmasp could only field 7,000 men (of dubious loyalty) and a few cannons. The Ottomans seized the Safavid capital Tabriz, crossed Kurdistan and captured Baghdad. Tahmasp avoided direct confrontation with the Ottoman army, preferring to harass it then retreat, leaving scorched earth behind him. This scorched earth policy led to the loss of 30,000 Ottoman troops as they made their way through the Zagros mountains and Suleiman decided to abandon his campaign.[6]