How was Persia conquered by the Muslims?;-)?
There is more that one significant factor. Persia had indeed been in a war with Byzantium, but that didn’t destroy the war machine of either empire. It did however affect the population (especially the commoners) in what is today Iraq & Syria, they were both fed up with both empires. The introduction of Mazdakism had shattered people’s faith in Zoroastrism. Buddhism in the east & Christianity in the west didn’t achieve much success. Apparently people in the Persian empire were open for something new. On the Muslim’s side there had been some figures who played a major role in the campaign. I’ll only mention 2 of them: 1- Salman Al-Farisi: This noble Persian had a long journey in the Middle East where he used to seek knowledge. He had learned a lot about the Persians & the Byzantines. When he became a Muslim, Muhammad himself used him as an advisor, as well as the Caliph Omar. Salman served as the moral officer in the battle of Qadisiya. Later he supervised the construction of Kufa & Bas
