The tribe of Shammar (Šammar) is a tribal Arab Qahtan confederation, descended from the Yemeni tribe of Tayy as they originated in Yemen before migrating into present-day Saudi Arabia. It is the biggest branch of the Tayy tribe, and one of the largest and most influential Arab tribes. The historical and traditional seat of the tribe's leadership is in the city of Ha'il in what was the Emirate of Jabal Shammar in Saudi Arabia. In its "golden age", around 1850, the tribe ruled much of central and northern Arabia from Riyadh to the frontiers of Syria and the vast area known as Al Jazira in Northern Iraq.
One of the early famous figures from the tribe was the legendary Hatim Al-Ta'i (Hatim of Tayy; died 578), a Christian Arab renowned for generosity and hospitality who figured in the Arabian Nights. The early Islamic historical sources report that his son, Adiyy ibn Hatim, whom they sometimes refer to as the "king" of Tayy, converted to Islam before Muhammad's death. Another figure from Tayy during this period was Zayd al-Khayr, a prominent member of Tayy who is said to have led Tayy's delegation to Muhammad accepting Islam.
The Shammar are a tribal confederation made up of three main branches: the Abdah, the Aslam, and the Zoba. The tribe of Shammar are descendants of the Tayy tribe of Yemen. The earliest non-Arab sources refer to Arabs as Taits, thought of as referring to the Tayy, as Ayas ibn Quasiba, a ruler of ancient Iraq, had contact with both the Byzantine and Persian Empires. Since some sections of Tayy, and most of the Ghassanids and Muntherids, were present in Mesopotamia and the Levant prior to Muhammad's preaching of Islam in the early 7th century. In the Namārah Inscription (the second oldest pre-Islamic Arabic inscription, dating from 328 CE), the name "Shammar" is believed to refer to a city in Yemen, though it may refer to the city where the Himyarite King Shammar Yahri'sh lived, the present-day Rada (located about from Dhamar, an ancient historic site).