The Seljuk Turks
Nomadic people from central Asia who converted to Islam and prospered a soldiers for Abbasid caliphate. As Abbasid grew weaker, the Seljuk Turks grew stronger, moving into Iran and Armenia.
The Seljuk Turks had taken over the eastern provinces of Abbasid empire.
Turkish leader captured Baghdad and took command of the empire. Taking the name Sultan, this enabled the Seljuk Turks to hold real military and political power in the state.
Byzanines foolishy challenged the Turks and were defeaed at Manzikert.
Saladin, a new Muslim ruler, took control of Egypt and made himself Sultan, ending the Fatimid dynasty. Also established control over Syria and took the offensive against the crusader states in the area.
Saladin's army invaded Jerusalem and destroyed crusader forces along the coast of Palestine.