He was the first imam to rule after the destruction of the Nizari state by the Mongol Empire, and spent his life hiding his true identity.
[2] He was the youngest son of Rukn al-Din Khurshah, the last ruler of Alamut Castle, the centre of a Nizari Ismaili state until it was captured by the Mongol Empire in November 1256.
[2] With his father's execution, sometime in late spring 1257, Shams al-Din automatically succeeded him as imam.
[2] He kept his identity hidden, instead assuming the guise of a Sufi mystic (a common practice among the Nizaris at the time) and embroiderer, whence he is known traditionally by the nickname Zarduz.
[5] Shams al-Din died c. 1310, inaugurating an obscure period in Nizari history that lasted until the late 15th century.