Melchizedek, the king of Salem in the time of Abraham.
Many believe that Melchizedek was Jesus.
Melchizedek appeared in Genesis to the patriarch Abraham. Whether he actually existed as a person or as an abstraction remains a mystery.
Melchizedek first appeared in the Bible's Old Testament bringing bread and wine to Abraham after his victory in Genesis 14 over the four kings who had besieged Sodom and Gomorrah and taken his nephew Lot prisoner. In turn, Abraham gave Melchizedek as priest a tithe of ten percent of the bounty that he took in battle. Psalm 110:4 names Melchizedek as representative of the priestly line through which a future king of Israel's Davidic line was ordained.
The future king - in Christian belief, Jesus Christ - is referred to as a "priest forever after the order of Melchizedek".
Hebrews 7:3 in the New Testament refers to Melchizedek as a king "without father or mother or genealogy", a reference which some Christians take as referring to Melchizedek's true nature as an angel or even as Jesus himself, appearing thousands of years before his Earthly incarnation.
Some rabbinic scholars identify Melchizedek with Noah's son Shem. The account of Melchizedek given in the Dead Sea Scrolls has also divided scholars into two camps, one that touts his existence as a mortal man and another that identifies him with the archangel Michael.
According to LDS tradition, Melchizedek's blessing of Abraham at Salem is a priesthood authority whose keys were restored to Joseph Smith along with the keys of Aaron's priesthood.