Ubayd Allah ibn Yahya ibn Khaqan, Abbasid vizier
Abū al-Ḥasan ʿUbayd Allāh ibn Yaḥyā ibn Khāqān (Arabic: أبو الحسن عبيد الله بن يحيى بن خاقان) was an Abbasid official who served twice as vizier, under caliphs al-Mutawakkil and al-Mu'tamid.