Sultan Sahak's life is remembered through Yarsani devotional narrative rather than documented biography, and the Kalam-e Saranjam's own Perdiwari texts do not supply datable historical reference points; scholarship's own fifteenth century placement is explicitly provisional, and other readings diverge by centuries.
What would resolve this An external historical or archaeological record from the Hawraman region independently datable and naming Sultan Sahak, distinct from the devotional Kalam-e Saranjam tradition that presently supplies the only accounts of his life.
OpenHistory of the Yarsan/Ahl-e Haqq tradition, Kurdish historyM. Reza Hamzeh'ee, The Yaresan: A Sociological, Historical and Religio-Historical Study of a Kurdish Community