Abū Yazīd Ṭayfūr b. ʿĪsā b. Surūshān al-Bisṭāmī (d. 261/874–5 or 234/848–9), commonly known in the Iranian world as Bāyazīd Bisṭāmī, was a Persian Sufi, from north-central Iran. Known to future Sufis as Sultān-ul-Ārifīn ("King of the Gnostics"). Bisṭāmī is considered to be one of the expositors of the state of fanā, the notion of passing away in mystical union with the deity.
