Zaidiyya (Zaidi Muslims)

Zaidiyya (Arabic: الزَّيْدِيَّة, romanized: az-Zaydiyya), or Zaidism (adjective form Zaidi or Zaydi) is a denomination of Shia Islam that emerged in the eighth century following Zayd ibn Ali's unsuccessful rebellion against the Umayyad Caliphate. Zaydism is one of the three denominations of Shia Islam, the other two being Twelverism and Ismailism. The Zaydis and Ismailis constitute a minority within Shia Islam, in contrast to the Twelvers, who constitute the predominant denomination. 

Zaydism is typically considered the Shia branch that is closest to Sunni Islam, although the "classical" form of Zaydism (usually referred to as Hadawi) historically changed its stance on Sunni and Shia traditions multiple times, to the point where Zaydis' simply accepting Ali as a rightful successor to Muhammad was enough to consider them Shia. Zaydis regard rationalism as more important than Quranic literalism and historically were quite tolerant towards Shafi'i Sunnis, the jurisprudential school of about half of the Yemenis. Most of the world's Zaydis are located in northwestern Yemen, and Najran in Saudi Arabia.