The struggle between the Ottoman Empire and Safavid Persia over Iraq, culminating in the pivotal Treaty of Zuhab in 1639, is a critical chapter in the region's history, marked by fierce battles, shifting allegiances, and significant cultural and political impacts. This period reflects the intense rivalry between two of the most powerful empires of the 16th and 17th centuries, underscored by both geopolitical interests and sectarian differences, with the Sunni Ottomans clashing against Shia Persians.

In the early 16th century, with the rise of the Safavid dynasty in Persia, led by Shah Ismail I, the stage was set for prolonged conflict. The Safavids, embracing Shia Islam, positioned themselves in direct opposition to the Sunni Ottomans. This sectarian divide added a religious fervor to the ensuing conflicts. The year 1501 marks the establishment of the Safavid Empire, and with it, the beginning of the Persian campaign to spread Shia Islam, directly challenging the Ottoman Sunni hegemony.

The first significant military encounter between the two empires occurred at the Battle of Chaldiran in 1514. The Ottoman Sultan Selim I led his forces against Shah Ismail, resulting in a decisive Ottoman victory. This battle not only established Ottoman supremacy in the region but also set the tone for future conflicts. Despite this early setback, the Safavids were undeterred, and their influence continued to grow, particularly in eastern parts of the Ottoman Empire.

Iraq, with its religious significance to both Sunni and Shia Muslims and its strategic location, became a primary battleground. In 1534, Suleiman the Magnificent, the Ottoman Sultan, captured Baghdad, bringing Iraq under Ottoman control. This conquest was significant, as Baghdad was not only a key trade center but also held religious importance. However, the control of Iraq oscillated between the two empires throughout the 16th and 17th centuries, as each side managed to gain and lose territories in various military campaigns.

The Safavids, under Shah Abbas I, made significant gains in the early 17th century. Abbas I, known for his military prowess and administrative reforms, recaptured Baghdad in 1623. This capture was part of a broader strategy by the Safavids to regain territories lost to the Ottomans. The fall of Baghdad was a substantial blow to the Ottomans, symbolizing the shifting power dynamics in the region.

The fluctuating control over Baghdad and other Iraqi cities continued until the signing of the Treaty of Zuhab in 1639. This treaty, a landmark agreement between Sultan Murad IV of the Ottoman Empire and Shah Safi of Persia, finally brought an end to the protracted conflict. The Treaty of Zuhab not only established a new border between the Ottoman and Safavid empires but also had significant implications for the region's demographic and cultural landscape. It effectively recognized Ottoman control over Iraq, with the boundary drawn along the Zagros Mountains, which came to define the modern-day border between Turkey and Iran.