Teachings of the Prophet Joseph Smith, pg. 166; “There are two Priesthoods spoken of in the Scriptures, viz., the Melchizedek and the Aaronic or Levitical. Although there are two Priesthoods, yet the Melchizedek Priesthood comprehends the Aaronic or Levitical Priesthood, and is the grand head, and holds the highest authority which pertains to the priesthood, and the keys of the Kingdom of God in all ages of the world to the latest posterity on the earth; and is the channel through which all knowledge, doctrine, the plan of salvation and every important matter is revealed from heaven.”
Hebrews 5:5-6; “So also Christ glorified not himself to be made an high priest; but he that said unto him, Thou art my Son, to day have I begotten thee. 6 As he saith also in another place, Thou art a priest for ever after the order of Melchisedec.”
Only TWO people ever held the Melchisedec priesthood. Melchisedec and Jesus.