Christology is the study of the work and teachings of Jesus of Nazareth in order to discern his nature and relationship to the Judeo-Christian God, as well as his role in human history. It focuses on the life and ministry of Jesus as it affects Christian theology and eschatology. Issues surrounding the nature and role of Jesus as the Christ, the Greek term for annointed, have been debated throughout history. Christology can be divided into three main historical periods, apostolic, post-apostolic and medieval, which represent one continual dialogue. A number of these arguments have been at the root of major schisms within the Christian Church during history.
Apostolic Christology can be traced to the writings of the apostles, mainly the Gospel of John. Whereas the first three Synoptic Gospels (Matthew, Mark and Luke) are primarily focused on the humanity of Jesus, the Gospel of John is principally concerned with the divinity of Jesus. The concept of Logos, from the Greek derivation for word, refers to the Divine words through which all things in creation are believed to be made. It is derived directly from the first chapter of John, who proposes Jesus as Logos, as well as his pre-existence from before creation.
Apostolic Christology is also heavily influenced by the writings of Paul, which reiterate the nature of Jesus as Kyrios, the Greek term for God or Lord and advance the idea of Cosmic Christology or the ramifications that the life and death of Jesus had for the cosmos. According to Jewish teachings, the role of the Messiah is to implement God's influence on history, whereas Hellenistic teachings extol the role of Christ as the primary mover in the universe and the foremost of all creation [Colossians 1:15].
Post-apostolic Christology, or the patristic era, covers the period of 100 to 325 as well as several debates as to the exact nature and divinity of Jesus. Several schools of thought were ongoing during this era. According to the teachings of Docetism, Jesus only appeared to be human, and as his nature was divine, he did not truly suffer or die a human death. Gnosticism also denied that Jesus was truly human and maintained that his role was to impart divine knowledge to humanity. Both Arianism and Ebionism, in contrast, argued against the divinity of Jesus, pre-existence and resurrection of Jesus. Ignatius of Antioch (d. circa 110) proposed the teaching that the "reality of salvation depends on the reality of the humanity of Jesus" whereas Irenaeus of Lyons (d. circa 200) stated that without the divine aspect, there is no salvation through Jesus.
Due to schisms brought about during this era, ecumenical councils convened during the next two centuries to settle the issues. The First Council of Nicaea convened in 325 to address the concept of the Trinity, or Godhead. It was decided that there is indeed one God assembled into three persons (Father, Son and Holy Spirit), while simultaneously condemning Arianism and similar schools of thought. Additionally, it concluded that the person of Jesus Christ was fully divine and of the same makeup as the person of God the Father, but also fully human. These concepts are codified in the Nicene Creed and were ratified five decades later at the First Council of Constantinople (381).
Nearly a century later, the First Council of Ephesus (431) was called to settle a dispute between the Patriarch of Constantinople, Nestorius, and Cyril, the Patriarch of Alexandria. At the time, the doctrine of Nestorianism was creating a schism regarding the relationship between Christ's human and divine natures. During the convention, several theories were presented: the concept of pure coexistence of two disparate natures (hypostasis) versus the complete separateness of two natures (Nestorianism), as well as the existence of only one, unique nature (monophysitism) versus two natures merged as one (miaphysitism). At the conclusion, the Council condemned Nestorius' teaching of the disparate natures of Christ and affirmed that Jesus is eternal, the son of God, was born of the Virgin Mary, suffered, died and was raised from the dead. It issued the Communicatio Idiomatum, confirming both natures of Christ, as well as the dictate of the "hypostatic union," which confirmed the pure coexistence of two disparate natures of Christ.
One of the main developments in Christology during the Middle Ages, was the introduction of the concept of the Christ as teacher/mentor, or in other words, a human in all aspects with the exception of the lack of a sin nature, as well as a "victor of death" and/or "vanquisher of the Devil." Christological tenets such as the impeccability and fullness of grace, the perfect wisdom and knowledge of Christ and the finite limitations of the human mind became expanded into medieval doctrines. The concepts necessitate the need to have a "personal" relationship with the figure of Christ, especially for the avoidance of eternal damnation and attainment of salvation.