Caliphate
After the Ottomans lost a war with the Russian Empire they signed a peace treaty with Russia in 1774.  The Sultan had to surrender large territories, including ones with large Muslim populations, such as Crimea, to the Russian Empire.  However, Sultan Abdul Hamid I claimed a diplomatic victory by assigning himself the protector of Muslims in Russia as part of the peace treaty.  Russia, meanwhile, was the protector of Christians in the Ottoman Empire.  This was the first time the Ottoman caliph was acknowledged as having political significance outside of Ottoman borders by a European power.  Although the Ottoman borders were shrinking, the powers of the Ottoman caliph increased.