The Ottoman Empire was at full power in the early 1500s. Around then, a group of Muslims called the Safavids (sah-FAH-weeds) took over Persia, which is now Iran.
As the Safavids waged war on lands east of the Ottoman Empire, their desire for conquest brought them into conflict with the Ottomans. It wasn’t just about control of territory. The Ottomans and Safavids had different beliefs, even though both groups followed Islam.
The conflict was based on an old disagreement Muslims had about who should be allowed to become caliph. In the mid-600s, Islam split into two groups because of this argument. The Shia (SHEE-ah) thought only Muhammad’s descendants could become caliphs. But the Sunni (SOO-nee) didn’t believe caliphs had to be related to Muhammad. Safavid leaders were Shia, and the Ottomans were Sunni. As the Safavids began pushing into new territory, the Ottomans became determined to keep Shia beliefs from spreading.
