They include ʿĀd (), Thamûd (), Tasm, Jadis, Imlaq and others. Jadis and Tasm perished because of genocide. 'Aad and Thamud perished because of their decadence, as recorded in the Quran. Archaeologists have recently uncovered inscriptions that contain references to Iram dhāṫ al-'Imād (, Iram of the Pillars), which was a major city of the 'Aad. Imlaq is the singular form of 'Amaleeq and is probably synonymous to the biblical Amalek. "Pure Arabs" () or Qahtanites from Yemen, taken to be descended from Ya'rub ibn Yashjub ibn Qahtan and further from Hud. "Arabized Arabs" () or Adnanites, taken to be the descendants of Ishmael son of Abraham. Arabians are most prevalent in the Arabian Peninsula, but are also found in large numbers in Mesopotamia (Arab tribes in Iraq), the Levant and Sinai (Negev Bedouin, Tarabin bedouin), as well as the Maghreb (Eastern Libya, South Tunisia and South Algeria) and the Sudan region. This traditional division of the Arabs of Arabia may have arisen at the time of the First Fitna. Of the Arabian tribes that interacted with Muhammad, the most prominent was the Quraysh. The Quraysh subclan, the Banu Hashim, was the clan of Muhammad. During the early Muslim conquests and the Islamic Golden Age, the political rulers of Islam were exclusively members of the Quraysh. The Arab presence in Iran did not begin with the Arab conquest of Persia in 633 CE. For centuries, Iranian rulers had maintained contacts with Arabs outside their borders, dealt with Arab subjects and client states (such as those of Iraq and Yemen), and settled Arab tribesmen in various parts of the Iranian plateau. It follows that the "Arab" conquests and settlements were by no means the exclusive work of Arabs from the Hejaz and the tribesmen of inner Arabia. The Arab infiltration into Iran began before the Muslim conquests and continued as a result of the joint exertions of the civilized Arabs (ahl al-madar) as well as the desert Arabs (ahl al-wabar). The largest group of Iranian Arabs are the Ahwazi Arabs, including Banu Ka'b, Bani Turuf and the Musha'sha'iyyah sect. Smaller groups are the Khamseh nomads in Fars Province and the Arabs in Khorasan. The Arabs of the Levant are traditionally divided into Qays and Yaman tribes. This tribal division is likewise taken to date to the Umayyad period. The Yemen trace their origin to South Arabia or Yemen; they include Banu