Qizilbash or Kizilbash (sometimes also Qezelbash or Qazilbash) is the label given to a wide variety of Shi'i militant groups that flourished in Azerbaijan,Anatolia and Kurdistan from the late 15th century onwards, some of which contributed to the foundation of the Safavid dynasty of Iran.
The word Kızılbaş is Ottoman Turkish (قزلباش; Turkish pronunciation: [kɯ.zɯɫ.baʃ]), meaning "Crimson/Red Head[ed]". The expression is derived from their distinctive twelve-gored crimson headwear (tāj or tark in Persian; sometimes specifically titled "Haydar's Crown" تاج حیدر / Tāj-e Ḥaydar), indicating their adherence to the Twelve Imams and to Shaykh Haydar, the spiritual leader (sheikh) of the Safaviyya movement in accordance with the Twelver Shi'i doctrine of the Imamate. The name was originally a pejorative label given to them by their Sunni Ottoman foes, but soon it was adopted as a provocative mark of pride.
The origin of the Qizilbash can be dated from the 15th century onward, when the spiritual grandmaster of the movement, Haydar (the head of the Ṣafawiyyah Sufi order), organized his followers into militant troops.