The concept of Sophia has been championed as a key part of the Godhead by some Orthodox religious thinkers. These included Vladimir Solovyov, [[Pavel Florensky]], [[Nikolai Berdyaev]], and [[Sergius Bulgakov]] whose book ''Sophia: The Wisdom of God'' is in many ways the apotheosis of [[Sophianism|Sophiology]]. For Bulgakov, the Sophia is co-existent with the [[Holy Trinity]], operating as the feminine aspect of God in concert with the three masculine principles of the Father, the Son, and the Holy Spirit. [[Vladimir Lossky]] rejected Solovyev and Bulgakov's teachings as error. Lossky states that Wisdom as an energy of God (just as love, faith, and grace are also energies of God) is not to be ascribed to be the true essence of God, to do so is to deny the apophatic and incomprehensibility of God as God's essence.<ref>This was the basis of the theological development of Fr. Bulgakov, and also his fundamental error: for he sought to see in the energy of Wisdom (Sophia), which he identified with the essence, the very principle of the Godhead. In fact, God is not determined by any of his attributes: all determinations are inferior to Him, logically posterior to His being in itself, in its essence. pgs 80-81 The Mystical Theology of the Eastern Church, by Vladimir Lossky SVS Press, 1997. (ISBN 0-913836-31-1) James Clarke & Co Ltd, 1991. (ISBN 0-227-67919-9) </ref> Sophiology is contrary to the official view of the Orthodox Church, and Bulgakov's work was denounced by the [[Russian Orthodox Church|Russian Orthodox]] authorities as [[Heresy|heretical]].<ref > Text available online [http://www.intratext.com/IXT/ENG0824/_P2O.HTM]</ref>