The metaphor of the Virgin as Christ's throne goes back at least as far as the 3rd century and Gregory Thaumaturgus' second homily on the Annunciation: "Thy praise, o most holy Virgin, surpasses all laudation, by reason of the God Who received the flesh and born man of thee. To thee every creature, of things in heaven and things on earth and things under the earth, Offers the meet offering of honor. For thou hast been indeed set forth as the true cherubic throne." ("Cherubic throne" refers to psalm 80:1.)
Methodius' oration concerning Simeon and Anna (also 3rd century) speaks of Virgin as the Child's "Virginal throne."
The identification of Christ with Wisdom itself is based on typological reading of the portraits of Wisdom in Proverbs 8:1-9:6 and in Ecclesiasticus 24 (which speaks of the "Throne" of Wisdom at verse 7 and verse 34.)
