books.google.fr - Volume 4 is a survey of every aspect of the civilisations which flourished in the Iranian region from the Arab conquests to the Saljuq expansion: in particular, it studies the gradual transition of Iran from Zoroastrianism to Islam, the uniting of all Iranians under one rule, the flowering into full...https://books.google.fr/books/about/The_Cambridge_History_of_Iran.html?hl=fr&id=hvx9jq_2L3EC&utm_source=gb-gplus-shareThe Cambridge History of Iran