Council of Chalcedon (451)

St. Leo the Great, author of Leo's Tome

Issues

This council was called just a few years after the Council of Ephesus and was held in October of 451. It was primarily an immediate response to the Second Council of Ephesus of 449, also called the Robber Council. The Robber Council was rejected by the East and West, although it is still regarded as valid in Oriental Orthodoxy. 

One of the issues dealt with at the Council of Chalcedon was the nature of Christ. The Robber Council had declared that Christ was a single, divine being. Several bishops at the Chalcedon council maintained that Christ had hypostatic union, a divinity and humanity held in one being. Pope Leo I (later St. Leo the Great and Doctor of the Church) wrote on Christ's nature; his document, called Leo's Tome, was used in the council debates.

Results

The Oriental Orthodox who affirmed the Robber Council rejected this council. This was the first big schism within the Church. Constantinople (New Rome) was declared equal to Rome, making East and West more or less equal.

The council also made a clear statement on the nature of Christ, that he was in hypostatic union. This means Christ is one person but has two natures, God and man simultaneously. There were also several disciplinary statements for the clergy and religious orders. This included forbidding monks or nuns to marry. It also stipulated that a woman must be at least 40 before being ordained deaconess.

Heresies

The main heresy condemned at this council was really what had been affirmed at the Robber Council and deals with the nature of Christ. Monophysitism states that Christ is one person and has one nature. This is almost the opposite of the Nestorian heresy that was condemned at the First Council of Ephesus just 20 years earlier. Nestorians hold that Christ is two people (God and man at separate times) with two natures. Churches centered in the Church of Alexandria (Coptic Orthodox and Oriental Orthodox) still hold to the Second Council of Ephesus instead of the Council of Chalcedon.

Misc.

It’s clear that there is still a lot of “figuring it all out” going on, even though the faith is about 400 years old at this point. There are lots of disciplinary rules laid out about how clergy should act and how bishops respect one another’s territory. It also shows the beginning of fragmentation. While the other councils showed that there were wildly different theological views floating about, there was the idea that councils would standardize and unify beliefs. However, the Robber Council, followed immediately by the Council of Chalcedon shows that groups will not always submit to council decisions.