What is "saphrax"

Saphrax (died 400) was a Greuthungi chieftain, who led the tribe along with Alatheus. Both names appear to have been Alanic; they may have been Sarmatian/Alan. After the death of the King Vithimiris while fighting against the Huns in 376, Alatheus and Saphrax became regents and guardians of Vithericus, infant son of Vithimiris. He and Alatheus commanded the Greuthungi, while Fritigern commanded the Thervingi, numbering an army of 10,000 (according to contemporary Ammianus Marcellinus) in the Battle of Adrianople in 378 against the Roman Empire. It is theorized that Saphrax led a Hun-Alan contingent. Ending in defeat, many of their followers were settled in Pannonia Prima. Remnants were recruited into the Roman army.