Tayy (/ALA-LC: "Ṭayyi’"), also known as Ṭayyi, Tayyaye, or Taiyaye, is a large and ancient Arab tribe, whose descendants today are the tribe of Shammar (and many other tribes), who continue to live throughout the Middle Eastern states of the Arab world and the rest of the world. The "nisba" (patronymic) of Tayy is "aṭ-Ṭāʾī" (). The Tayy's origins trace back to the Qahtanites and their original homeland was Yemen although Sebeos later named Iraq as Tachkastan after them. In the 2nd century CE, they migrated to the northern Arabian mountain ranges of Jabal Aja and Jabal Salma, which then collectively became known as "Jabal Tayy" (later "Jabal Shammar"). The latter continues to be the traditional homeland of the tribe until the present day. They later established relations with the Sassanid Persian and Byzantine empires. Though traditionally allied with the Sassanids' Lakhmid clients, the Tayy supplanted the Lakhmids as the rulers of Al-Hirah in the 610s. In the late 6th century, the Fasad War split the Tayy, with members of its Jadila branch converting to Christianity and migrating to Syria where they became allied with the Ghassanids, and the Ghawth branch remaining in Jabal Tayy. A chieftain and poet of the Al Ghawth, Hatim al-Ta'i, is widely known among Arabs until today.