--becomes the "Hidden Imam,"basis of "Twelver"& Iranian Shi'ismThe Shi'a, or "Faction" of 'Ali held that he was the proper Successor to the Prophet and that only his descendants qualified for the office. Soon, he and his successors were also believed to have a unique divinely inspired understanding of the meaning of the Qur'an. Thus, the Shi'ite office of Imam became a source of doctrinal authority such as was missing from Orthodox Islam, which relied on tradition and consensus to establish Islamic law and doctrine. The line of Imams splits, however, when the Seventh, Isma'il, is rejected by much of the community. The Seveners, nevertheless, had the most spectacular successes of Shi'ism in the Middle Ages. Today, the Agha Khan heads a Sevener community in India. The collateral line ended with the Twelfth Imam, who disappeared in 878. Although probably kidnapped and murdered by the Abbasid Caliph, he was believed by his followers to have gone into deathless "Occultation," preparing to return as the "Rightly Guided One," the Mahdi, to usher in the Apocalypse. In time, this Twelver Shi'ism was used by the Safavids to establish a durable national monarchy in Iran. In 1848, it had been 1000 Islamic lunar years since the Occultation, and the return of the Hidden Imam was widely expected. Various figures appeared as the Imam, including the Bab ("Gate"), from whom the Babi and Baha'i faiths derive. The source of doctrinal authority in Iranian Shi'ism became the Ayatollahs, who were not individually believed to be the Hidden Imam but were thought to communicate with him. The Ayatollah Khomeini was able to use his position to overthrow the last Shah in 1979 and establish a theocratic "Islamic Republic."OMAYYAD CALIPHSMu'awiya I661-680assumes caliphate at death of 'Ali, moves capital to Damascus; Arab aristocratic government; Siege of Constantinople, 674-677; attacks in India, 677Yazid I680-683Mu'awiya II683-684Marwan I684-685Uqba ibn Nafi' founds Qayrawan, 663/4; reaches the Atlantic, killed & Army annihilated by Berber Kusayla, 683'Abd 'al-Malik685-705Builds the Dome of the Rock in Jerusalem, finished 691/692; Conquest of Armenia, 693; silver dirham & gold dinar first minted, 695; Fall of Carthage, 698, 705; H.assan ibn al-Nu'man defeated by Berber (possibly Jewish) prophetess al-Kahina (Dahiyah, Dahia, or Dhabba), driven out of North Africa, after 698; Kahina defeated, Berbers convert, 702al-Walid I705-715Builds the Omayyad Mosque in Damascus, 706-715; Spain falls to Islam, end of Visigoths, invasion of India, 711Sulayman715-717Siege of Constantinople, 717-718'Umar II717-720Yazid II720-724Hisham724-743defeat, 725, & explusion, 737, from India; defeated by Khazars, Ardebil, 730; but defeated and subjected Khazars, 737-c.740al-Walid II743-744Yazid III744'Ibrahim744Marwan II744-750Abbasid revolution, Omayyads overthrown and massacred (except in Spain); end of Arab empire, 750; Battle of Talas, 751, T'ang Dynasty Chinese defeated, but no further advance into Central AsiaUnder the Omayyads the House of Islam was undoubtedly an Arab Empire, with only a very secondary interest in winning converts to the Faith. Indeed, many Arabs believed that Muh.ammad had simply been a Prophet for the Arabs, as Moses had been the Prophet for the Israelites, and this view was reflected in the practice that newly converted Moslems needed to be affiliated with an Arab tribe.