al-Ramahurmuzi

Abu Muhammad al-Hasan ibn Abd al-Rahman ibn Khallad al-Ramahurmuzi — often called Ibn al-Khallad — was a Persian scholar of hadith (the reports of the sayings and deeds of the Prophet Muhammad) and a qadi, a Muslim judge. His name points to his home town of Ramhormoz in Khuzistan, in what is now southwestern Iran.

The details of his life are thin. His birth date is not recorded; modern scholars estimate it around 260 AH (about 871 CE) by working backward from the death dates of his reported teachers, so this figure is an approximation, not an attested fact. He is said to have begun hearing hadith around 290 AH (903 CE), learning first from his father and then from other traditionists of the region. He served for a time as a judge, though the sources give almost no detail and do not say where.

His lasting fame rests on a single book, al-Muhaddith al-Fasil bayna al-Rawi wa al-Wai ("The Traditionist Distinguishing Between the Transmitter and the Discerning Scholar"). It is widely regarded by both classical and modern authorities as among the earliest — many say the first — comprehensive works devoted to the principles and ethics of hadith transmission, and it shaped the whole later genre.

His death date is uncertain: tradition places it before, or in, 360 AH (971 CE), while the historian al-Dhahabi could not fix it precisely and leaned toward the 350s AH.