The document summarizes three Islamic empires that emerged in the post-Mongol era: the Ottoman, Safavid, and Mughal Empires. It notes that all three were "gunpowder empires" that utilized new military technologies like cannons. It also states that they shared some similarities in their political structures, with absolute rulers who held both political and religious authority. However, the empires were also rivals at times, as demonstrated by a hostile letter between the Ottoman Sultan and Safavid ruler. Their social structures also shared the common element of slavery.