He ruled over the city of Salem, which may have been ancient Jerusalem. It is evident that the writer of Hebrews uses Melchizedek as an illustration of the authority and ministry of the Messiah, who also combined the offices of priest and king. The writer asserts that Melchizedek's authority is greater than that of the priesthood descended from Levi. When Abraham submitted to the higher authority of Melchizedek, Levi, as Abraham's descendant did as well. As a man, he had parents, but the family records were lost to posterity and the writer to the Hebrews uses this argument from silence to illustrate the superiority of Messiah's perpetual priesthood.
Genuine typology requires that a type have historical reality and a prophetic element.
Melchizedek satisfies both of these requirements. He is described as an historical person, whose contemporaries were likewise historical kings. And Hebrews 7 indicates that Melchizedek's priesthood looked forward, in prophetic fashion, to Messiah's greater priesthood. The Aaronic priests grew feeble and eventually died. But Messiah conquered death.