Regional powers

Regional powers
The Abbasids soon became caught within a three-way rivalry of Arabs, Persians and the immigrant Turks.[10] In addition, the cost of running a large empire became too great.[11] The political unity of Islam began to disintegrate. The Emirates, still recognizing the theoretical leadership of the caliphs, drifted into independence, and a brief revival of control was ended with the establishment of rival caliphates. Eventually the Abbasids ruled as puppets for the Buwayhid emirs. During this time, great advancements were made in the areas of astronomy, poetry, philosophy, science, and mathematics.