The doctrine of the church changed somewhat during this century. Many of the councils which were held to settle theological problems actually added more because of the lack of order and decisions that came out of the councils. We find in this century the growth of veneration for departed saints. We find the beginning of the idea of celibacy of the priests, the worship of images and relics, a number of superstitions, the substitution of worship of the martyrs for the pagan gods of old. Pilgrimages to the Holy Land, and to holy places, and the sale of dirt and images from the Holy Land became common place.
While in the Third Century the idea of withdrawal and self-contemplation was brought out, this idea bloomed in the Fourth Century, and these individuals were banded into groups and into monasteries. When Constantine ordered tearing down the temples of the pagans, there appeared in their places great Christian churches, richly adorned with pictures and images. It was looked upon as an essential part of religion to have as many churches as possible in each country, and in order to build these churches, it was necessary to have the right of patronage to bring in the money.
The church worship service varied according to the whim of the Bishop. This was before the Bishop of Rome had secured enough authority to publish the model of all worship services. There were many liturgies used in the service, the Psalms were now used as hymns, Communion was celebrated as often as two or three times a week and at funerals, the people were allowed and even encouraged to applaud for good sermons.
There were many arguments in the church during this century, and even fights. Most of the splits were because of sects which followed one man, and were excommunicated from the church. Only a few lasted over a few years. However, one group in Africa called the Donatists after their leader Donatus remained. A part of their group was very bloodthirsty and killed many of their opponents. But they lost their influence by the end of the century. We see by the end of this century the blueprint of the Catholic Church.