The city was occupied by arabs after the final defeat of iranians.
British Dictionary definitions for iranians
a native, citizen, or inhabitant of Iran
a branch of the Indo-European family of languages, divided into West Iranian (including Old Persian, Pahlavi, modern Persian, Kurdish, Baluchi, and Tajik) and East Iranian (including Avestan, Sogdian, Pashto, and Ossetic)
Also Persian, Farsi. the modern Persian language
relating to, denoting, or characteristic of Iran, its inhabitants, or their language; Persian
belonging to or relating to the Iranian branch of Indo-European