Which council took place in 553 AD and reaffirmed the decisions of Chalcedon?

The council that took place in 553 AD and reaffirmed the decisions of Chalcedon is the Fifth Ecumenical Council, also known as Constantinople II. This council was significant as it sought to address the ongoing disputes that followed the Council of Chalcedon in 451 AD, which defined the two natures of Christ—divine and human—and caused a division among various Christian sects.

At Constantinople II, the council reaffirmed the Christological definitions established at Chalcedon, emphasizing the importance of maintaining these teachings against heretical interpretations that arose in the years following Chalcedon. Additionally, the council addressed the controversies regarding the Three Chapters, which were writings that some believed undermined the definitions set out by Chalcedon. By affirming these decisions, Constantinople II played a crucial role in striving for unity within the church and resolving theological disputes that were causing divisions.

In contrast, the other councils mentioned were significant in their own rights but did not take place in 553 AD nor focused on reaffirming Chalcedon. The Second Ecumenical Council took place in 381 AD, primarily addressing the Nicene Creed and issues regarding the Holy Spirit. The First Ecumenical Council occurred in 325 AD, focusing