Hormuzan, after being threatened to choose between death and Islam, converted to Islam.[9] Hormuzan was later suspected as being part of the assassination of the Rashidun caliph Umar, and was put to death.[7] By 651, most of Iran was under the control of the Arabs, and Yazdegerd III had been assassinated under the orders of his servant Mahoe Suri, an aristocrat from the Suren family, who served as the governor (marzban) of Merv, a powerful Sasanian stronghold. In 654, all of Iran was under the possession of the Arabs.