Abu Abdillah Siraj al-Din Umar b. Akmal al-Din al-Gilani al-Khalwati (d. 800/1397 [?]) was born in Lahijan in Gilan; he became a disciple of his uncle Akhi Muhammad and, renowned for his long retreats (khalwa), became the founding pir of the Khalwatiyya, one of the most widespread Sufi orders of the Islamic world. According to the TDV encyclopedia he died in Tabriz and was buried in the cemetery of the Mir Ali Zawiya; some studies instead place his grave at the Pir Umar Sultan shrine in Avakhil village near Shamakhi. As the burial place is disputed, no coordinates are given. (Sources: TDV 'Umar al-Khalwati'; TDV 'Khalwatiyya'.)