How did religious division intensify the ottoman-safavid state rivalry?

Religious beliefs have highly influenced the political and hierarchical structures in both Ottoman and Safavid Persia empires. Although both states were of Islamic religion, they belonged to different branches, Sunni and Shia. These branches differ over the choice of Muhammad's successor, which subsequently acquired broader political significance, as well as theological and juridical dimensions. Sunni Muslims believed that Muhammad didn’t clearly appoint a successor, which is why there isn’t hereditary succession law in Ottoman Empire. This contrasts with the Shia Muslims view, which holds that Muhammad appointed his son-in-law and cousin Ali ibn Abi Talib to succeed him. They believed that the empire should be led by direct successor of Muhammad’s line. Differences between these two branches affected the politics, as Shia Muslims weren’t religiously tolerant to other confessions and considered them for heretics, even the other branches of Islam. This resulted in the besieged of Bagdad, which was followed by the massacre of a large part of its Sunni Muslim inhabitants, as it was endeavored to transform Baghdad into a purely Shiite city. The besiege of Bagdad was the event that led to the Ottoman-Safavid war (1623–1639).

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