Apologies for the mistake earlier. Here are the summaries of the 3rd and 5th Ecumenical Councils:

The 3rd Ecumenical Council, held in 431 AD, condemned the teachings of Nestorius and affirmed that Mary, the mother of Jesus, was theotokos, meaning "God-bearer" or "Mother of God." The council also affirmed the dual nature of Christ, both fully divine and fully human, which were united in one person or hypostasis.

The 5th Ecumenical Council, held in 553 AD, condemned the teachings of the Three Chapters, which were writings of certain theologians that were seen as promoting Nestorianism. The council affirmed the dual nature of Christ and emphasized his unity as one person or hypostasis. It also condemned Origen, a theologian who taught that human souls existed before birth, among other controversial teachings.