Which council defined the doctrine that Jesus has two natures joined in a single person?

The Council of Ephesus, held in 431 AD, is the gathering that defined the doctrine concerning the dual natures of Jesus Christ, affirming that He exists as both fully divine and fully human within a single person. This was a critical moment in Christian theology as it sought to clarify the understanding of Jesus' identity and nature amidst various interpretations and controversies.

The council dealt primarily with the teachings of Nestorius, who proposed that there were two separate personae within Christ, which was deemed heretical. The council ultimately upheld the traditional understanding that while Jesus possesses two distinct natures—divine and human—these natures are united in one person, affirming the Christian belief in the hypostatic union. This theological foundation remains a key tenet of Christology in Christianity.

In contrast, the other councils listed had different focuses. The Council of Trent was primarily concerned with reforming church practices in the 16th century and addressing issues raised by the Protestant Reformation. The Council of Nicaea, convened in 325 AD, dealt with the Arian controversy and established the Nicene Creed, focusing on the nature of Christ's divinity but not explicitly addressing the two natures. The Council of Constantinople, which