Relations between Great Seljuk State and Abbasid Caliphate and marriages between two dynasties

Great Seljukid State had been played a major role on the making and development of Turko-Islamic civilization. Seljuk Sultans introduced themselves as the proponents of Sunni Islam shortly after the foundation of the State and thus took on the task of defender of Abbasid Caliphate. They defended their cause against Shia threats in any manner voluntarily. Abbasid Caliphs also saw this newly founded state as their savor. Seljuk Sultans presented themselves as mundane leaders and Caliphs as religious leaders. They also sought alliance through marriages with Caliphate in order to unite the two powers. Thus two dynasties had both closer relations and stood strongly against other states with the union of political and religious authorities.