Conquering Fars regions from Muslim entry to the end of the Rashidun caliphs

Fars was the most important province in Iran that was considered at the time of the second Caliph Omar ibn Khattab and was attacked on both sides of Bahrain and Basra. The five Fars regions conquered by the Muslims gradually. Islamic resources report different years for the conquests and the name of the conquerors of the Fars regions. It represents the insurrections of the inhabitants of these regions after each conquest. The purpose of this research is Study of conquest process in Fars and different reports among Islamic writers in the conquest years and the name of the conquerors of the Fars in the Rashidun caliphs' era. The research question is: What reasons is there for the different reports in the year of conquest and the names of the victors of these furnaces from the time of the second caliph to the end of the Rashidin caliphate? Research methodology is descriptive-analytical. this result was obtained that to the collapse of the Sassanian Empire, change the internal structure of government and disorder and the collapse of government, heavy tribute (Bāj) and tax (Kharāj), misbehavior of caliphate agents in five Fars regions, cruelty and brutality of some conquerors in conquering regions, also internal disagreements among Muslim Arabs, and tribal rivalries to achieve more power, they caused to rebel the people of Fars. They were suppressed by different commanders and conquerors in different years. So, they were registered different reports about the conquest years and the name of the conquerors in the resources.