2nd–3rd c.

Early Christian worship, baptism, and church order

The Sunday Eucharist was a joyful celebration of the resurrection. From the early 2nd century the communal meal (agape) gradually separated from the Eucharist proper. By the mid-3rd century the Eucharist had been reduced to bread and wine. The doctrine of Christ's real presence and the sacrificial character of the Supper had by then already taken shape (Ignatius, Justin, Irenaeus, Cyprian), without yet being disputed.

Baptism was usually performed at Easter by triple immersion after a lengthy catechumenate. Infant baptism is attested by Tertullian, who opposed it as an innovation, and by Origen. It received theological grounding from Cyprian, who linked it to the doctrine of original sin.

In parallel, the very concept of the Church changed during the 2nd century. The community as the "people of God" gave way to an understanding of the Church as an external organization headed by a bishop, the apostles' heir. The monarchical episcopate was established at Rome by 200. It separated bishops from presbyters, out of whom parish priests grew in the 3rd century.

The house-church excavated at Dura-Europos (256) is the earliest known purpose-built site of Christian worship.