The 5th Ecumenical Council, held in 553 AD, condemned the teachings of Nestorius, who held that there were two separate and distinct persons in the incarnate Christ. The council affirmed that Christ was one person with two natures, divine and human, which were united in one hypostasis.
The 6th Ecumenical Council, held in 681 AD, condemned the teachings of the monothelites, who held that Christ had only one will, a divine will. The council affirmed that Christ had two wills, divine and human, which were united in one hypostasis. The council also affirmed that Mary, the mother of Jesus, was theotokos, meaning "God-bearer" or "Mother of God."