a part of a tribal confederation called the Sum'ay, and they worshipped the god Ta'lab. Banu Hamdan was mentioned in Sabaic inscriptions as qayls ("chiefs") of Hashid, later Banu Hamdan acquired control over a part of Bakil and finally gave their clan name to a tribal confederation including Hashid and Bakil. In the late 3rd century Banu Hamdan (and, consequently, Hashid and Bakil) switched their alliance to Himyar. Later some groups of Hamdan migrated to Syria. Conversion to Islam In the year 622, Muhammad sent Khalid ibn al-Walid to Yemen to call them to Islam. Khaled managed to convert the Najrani and Tihami Yemenis to Islam but he didn't get a warm response from the Hamdani Yemenis of the highlands. So Muhammad delegated the task to Ali ibn Abi Talib, who was much more successful in converting the Hamdani Yemenis. After the death of Muhammad the Hamdan tribe remained Muslim and didn't join the ridda movement. After Ali, Power Vacuum in Yemen and the Imam Hadi The Hamdan tribe remained on the side of Ali, even after the martyrdom of Ali and later his sons. The tribes remained on alliance to Ali but didn't oppose the Ummayas or ally themselves with the other Shias. At that time Yemen was experiencing a great population movement forming the bulk of the Islamic Expansion mainly settling in southern Iraq. However, the majority of the Hamdan tribe remained in Yemen which later helped the Hashid/Bakil Hamdani tribes become the biggest local key player, benefiting from the departure of the bulk of the most powerful Nomadic Yemeni tribes of that time into North Africa/Spain in Wetsward movements that continued until the 13th century. By The 10th century the Imam al-Hadi Yahya bin al-Hussain bin al-Qasim (a scion of Imam al-Hasan, grandson of the Prophet) who, at Sa'da, in 893-7 C.E. arrived to the Northern Highlands on invitation from the Hamdan tribe and from that time till present day the Zaidi moderate Shia teachings became dominant in north Yemen. Modern history Many writers have referred to the Hashid and Bakil confederations as the "two wings" of the Zaidi imamate; in the sense that many of the tribes that belong to these confederations are and were strongly committed to Zaidi Islam, the imams were recognized – to a greater or lesser degree – as the heads of the Zaidi community and could, therefore, count on a measure