Safī al-Din's importance is attested in two letters by Rashid al-Din. In one, Rashid al-Din pledges an annual offering of foodstuffs. In the other, Rashid al-Din writes to his son, the governor of Ardabil, advising him to show proper consideration to the sheikh.
After Safī al-Din's death, leadership of the order passed to his son Sadr al-Dīn Mūsā, and subsequently passed down from father to son. In the mid-fifteenth century, the Safaviyya changed in character and became militant under Shaykh Junayd and Shaykh Haydar, launching jihads against the Christians of Georgia. Haydar's grandson, Ismail, further altered the nature of the order when he founded the Safavid empire in 1501 and proclaimed Twelver Shi'ism the state religion.