The Seljuk period refers to a significant era in medieval history, primarily during the 11th to 13th centuries, when the Seljuk Turks established a vast empire across parts of the Middle East, including modern-day Iran, Iraq, and Turkey. This period is marked by the expansion of the Seljuk state, which played a crucial role in the spread of Islam and the development of Persian culture. During the Seljuk period, the empire became a center for trade, culture, and learning. The Seljuks are known for their architectural achievements, including the construction of mosques and caravanserais, and for fostering the growth of cities like Isfahan. Their influence laid the groundwork for later empires, such as the Ottoman Empire.