Mamtur Al-Aswad was from the 2nd generation or Tabi’in. He was also referred to as Abu Salam Al-Habashi (the Abyssinian) even though his roots are from the Himyar tribe in Yemen. In earlier generations, sometimes Arabs with light skin would be referred to anyone with darker skin as Habashi as Abu Salam was described. Perhaps Abu Salam contained maternal Habashi roots given that Yemen had been occupied by Abyssinians for years prior to the birth of Prophet Muhammad (SAWS).
Abu Salam was a student of learned companions of the Prophet (SAWS) including ‘Ubada bin As-Samit (RA), who was also black. He resided in Bilad Ash-Sham (Greater Syria) and relayed ahadith that he learned.
During the khilafah of Bani Umayyah under Mu’awiyah bin Abi Sufyan, Muslims began to return back to tribal attachments in a strong way in which non-Arabs were seen as needing to be attached to an Arab tribe. In Tadhhib Al-Kamal by Al-Mizzi, it is stated that Mu’awiyah confronted the grandson of Abu Salam in Damascus, who was black in appearance, asking him who was his grandfather. He replied that it was Mamtur meaning Abu Salam. Mu’awiyah then asked him to who he was attached as if he was not an Arab. He then got angry with Mu’awiyah because he was an Arab.