Mary, Seat of Wisdom is one of the many titles of Mary in the Litany of Loreto.  Mary is given this title because Jesus, the Wisdom of God, once dwelt in Mary and after His death was laid in her lap.  Mary became the human throne of the one who reigns in Heaven.  She was also given this invocation because she knows what it is like to hold and love wisdom, as well as to live out wisdom.  Philosophy is called the pursuit or love of wisdom. Mary is, therefore, the philosophy of Christians for whoever desires to find true Wisdom must direct his/her love and endeavor to Mary. (Theotokos, 368)  St. Augustine is the first person to refer to Mary as the Seat of Wisdom.  This title does not make Mary the root of all wisdom, God alone is the root of all Wisdom. (James 1:5)

The feast day to celebrate this particular aspect of Mary is June 8.  

“All-holy Father, eternal God, in your goodness you prepared a royal throne for your Wisdom in the womb of the Blessed Virgin Mary; bathe your Church in the radiance of your life-giving Word, that, pressing forward on its pilgrim way in the light of your truth, it may come to the joy of a perfect knowledge of your love.  Grant this through our Lord Jesus Christ, your Son, who lives and reigns with you and the Holy Spirit, one God, forever and ever.”  Amen.