Ali al-Hujwiri
Abu al-Hasan Ali ibn Uthman al-Jullabi al-Hujwiri (Persian: ابو الحسن علی بن عثمان الجلابی الھجویری, romanized: Abū al-Ḥasan ʿAlī ibn ʿUthmān al-Jullābī al-Hujwīrī; c. 1009-1072/77), known reverentially as Data Sahib (Persian: داتا صاحب, romanized: Dātā Ṣaḥib), was an Islamic scholar and mystic who authored Kashf al-Mahjub, the earliest treatise on Sufism in the Persian language. Born in the Ghaznavid Empire, al-Hujwiri is believed to have contributed "significantly" to the spread of Islam in South Asia through his preaching.