The main foundation of the army in Iran before the central Asian tribes came to power was based on the military base of the tribes and local powers. Since Iran was considered a part of the Islamic countries and in fact the territory of the Caliphate, therefore it was under the command of the Abbasid Caliphate's army from a military point of view, but in Iran local Governors held power in different regions and each local power relied on the forces of their own military. Apart from the local forces, the Turkic slaves of the Central Asian tribes formed another military element. The transformation in Iran's military system started from the monarchy of Sultan Mahmud Ghaznavi. The military organization created by Sultan Mahmud was a new development in the structure of the country's military forces at that time. The soldiers of the new army not only received salaries, but also received a share of the trophies of war. The emergence of the army and its addition to the traditional structure of forces that had a tribal origin was the first important social feature of the rise to power of the Central Asian tribes, including the Ghaznavids and the Seljuqs, in Iran. The formation of the army led to an increase in military costs and, as a result, an increase in taxes. Tax collection was done by governors and local rulers. In this era, the right to own land was not recognized much by the government, and after taking an area, the heads of the tribes saw themselves as the lands' owners, and the conquered area was like a war booty for them, which had to be divided among the members of the tribe. During the Seljuk Empire, one of the problems that the central government was dealing with was the payment of monthly salaries of bureaucrats and soldiers; Therefore, in order to pay their salaries, the central government provided them by Iqta'. Since the beginning of the victory over the Ghaznavids, the Seljuks divided the provinces of the country among their leaders. The monarchs of the tribes often called themselves Malik, Amir or Shah. Few of these monarchs, whose history reached the Seljuq era, called themselves Atabak, such as the Eldiguzids, Salghurids, Shabankaras, Atabegs of Yazd, Atabaks of Great Lorestan and Atabaks of Little Lorestan. Domestic disputes and chaos among local governments were common in these days. Expansion of Sultan