What was Christianity like in the initial stages of its existence?
Viewed from a historic point of view, Christianity started as an offshoot of Judaism. Very early Christian churches worshipped in the homes of believers. All members shared their property with each other. As Jewish Christians, they continued to go to the Jewish temple to observe the Jewish worship patterns. In addition, they shared in meals based on the Lord's Supper within their groups.
All the believers were together and had everything in common. Selling their possessions and goods, they gave to anyone as he had need. Every day they continued to meet together in the temple courts. They broke bread in their homes and ate together with glad and sincere hearts, praising God and enjoying the favor of all the people. (Acts 2:45-47a)
As time passed and word of the new faith spread, Gentiles (non-Jews) started to join the converts. Based on Peter's vision and his presence as the Holy Spirit was given to Cornelius (a Roman centurion) and others in his household (Acts 10), the church leaders recognized that Gentiles were to be welcomed into the new faith and did not have to fulfill all the traditional Jewish practices (Acts 11:1-18).
As the Roman occupiers of Judea and surrounding provinces, in conjunction with the Jewish religious authorities, united in persecuting the new Christians, they were forced to flee for their lives or to hide their worship practices and beliefs.