The Heritage of the Blessed Virgin Mary

The story of the Blessed Virgin Mary's parents, Sts. Anne and Joachim, is told by the very early work usually referred to as the "Proto-evangelium of James".  A sermon by Pope Innocent III discusses the question of the lineage of the Blessed Virgin in terms of the Mosaic law:

"The genealogies given by Matthew and Luke do not seem to prove that Mary was of the lineage of [King] David nor even of the tribe of Judah.  But according to the law, through long custom, persons of different tribes could be joined in marriage, but their possessions and inheritances would not be joined together [cf. Numbers 36, 6-9], for two tribes, one priestly [Levi] and one royal [Judah] were joined together legally through a covenant.  Thus, Mary is said to be a relative of Elizabeth, who was of the daughters of Aaron [the tribe of Levi], and she was able to be married to Joseph, who was of royal lineage, of the house and family of David.  Now, although it be granted that Joseph and Mary were members of the same tribe, that of Judah, still it has not been proven that they were members of the same family.  Now, Joseph was descended from the line of David, and Mary could have descended from the same line, or she could have come from another family of that line than Joseph's.  Therefore, the prophets, filled with the Holy Spirit, wished to foretell clearly that Christ was to be descended from the house of David and from royal seed.  In Isaiah 11, 1, it is written that, 'A rod shall go forth from the root of Jesse' -- that is, from King David, who was the son of Jesse, and of royal heritage -- and 'a flower' -- Christ -- 'shall rise up from its root.'  Jeremiah 23, 5: 'I shall raise up to David a just branch, and he shall reign as king, and he shall be wise, and he shall do justice and judgment on the earth, and this will be the name which he is called: Our Just Lord.'  Our word 'Lord' is translated from the Hebrew Adonai, which is the name for God, and this Hebrew word is only used to indicate God.  Thus, it is proven that this 'branch' to David, which is Christ, is God.  In Revelation 5, 5, one of the elders says to John: 'Do not weep.  Behold, the Lion of the tribe of Judah, the Root of David, has prevailed.'  In 2 Timothy 2, 8, Paul says to Timothy: 'Remember that our Lord Jesus Christ has risen from the dead, of the seed of David, according to my Gospel.'  That which is written at the end of the Book of Numbers sufficiently shows that those women who had a part of the inheritance should wed not merely members of their tribe, but even of their same family: 'All the men should take their wives from the same tribe and family, and all the women should take their husbands from the same tribe, so that the inheritance may remain in the family' (Numbers 36, 1-9).  Now, Joachim and Anna did not have a male heir: their first-born was the Virgin Mary.  Thus, the inheritance belonged principally to her.  When the time came for the Holy One to marry, she married a just man from her tribe, according to the law.  And the Virgin Mary was from the same tribe and family as he." 

Thus, Mary seems to have a heritage in both the royal tribe of Judah and the priestly house of Levi, according to Innocent III, appropriate in that her Son would be both King and High Priest.