Ebrahim Pour Davoud
The question commonly asked with regard to the defeat of the Iranians by the Arabs is. How did the Iranians give up their ancient religion in just about a few centuries? And, How did the Persian with all their might loose the war against sixty thousand invading thugs?
Many reasons have been cited, the first among them being that; When a religion is new it cause excitement among its followers and this in itself leads to victory in what ever they attempt.
Second; the life of a society like humans can be distinctly divided into period of childhood, youth and old age. For the people of Iran 1350 years had passed since it became a nation it was in its old age and took many things for granted and as such had depleted its strength.
Iran was the only nation in the East that had stood against Europe and kept back the Romans. The last 400 years had been hard on the nation considering its long wars with Rome and other neighbours, while the Arabs had just formed a nation and were fresh.
Thirdly, The Sassanian royal family had become weak. Ghobad II had killed all the members of the royal family. There were no strong rulers left, in a period of 3 years 10 rulers, who included women and children, changed hands. Even before Yazdgard III was crowned at the age of 21 the Arabs were watching and waiting. The western part of the country, which included the Semitic race that was sympathetic to the Arabs, played an important role in Arab victory.
Fourthly: The Mazdiyasni religion by that time had become very ritualistic and difficult to maintain. A good part of the day was consumed in keeping oneself within the limits of the prescribed rituals for cleanliness. People were tired and were looking for ways to circumvent the rules.
In addition the abundance of wealth and the culture of enjoying life resulted in laziness and pride, and they paid no attention to the change in conditions across the border, among what they called, the lizard eating tribes of Arabia. All these conditions contributed to the downfall of the empire and its religion.