This message arose out of some comments on an earlier post reviewing Pagan Christianity? by Frank Viola and George Barna.
The authors of this book provide evidence that the earliest churches probably had a maximum attendance of around 35. That is based primarily on archaeological evidence. We know the first century Christians met in homes, we know the kinds of homes which were often used for such meetings, and we know how big they were. These gatherings were limited in size by the homes in which they met. As the Christian community in any area grew they would start new house-meetings.
According to the archaeological evidence, it was not until the early third century that Christians had any special buildings. The earliest identifiable Christian meeting place is the house-church of Dura Europos in modern Syria (pictured is the baptistery of the 3rd-century house church at Dura-Europos, now on display in the Yale University Museum, USA. This is the oldest Christian church ever discovered. The baptismal bath is visible. The surviving frescoes of the baptistry room are probably the most ancient Christian paintings.) It was simply a private home remodelled as a Christian gathering place around AD 232. This house was essentially a house with a wall removed between two bedrooms to create a large living area. This house could accommodate about 70 people (Pagan Christianity? page 14-15).
I don't think Viola and Barna are suggesting that our practice of meeting in special buildings is necessarily "wrong". They are simply saying that we cannot claim to be continuing or restoring a first century Christian practice if we do. The very nature of meeting in halls or special church-buildings affects the kind of meetings we have, and meetings in halls or special buildings have a remarkably different character to meetings held in homes around a meal table.
In my view, much of the intimacy of the early church/ekklesia was probably lost in the shift from homes to special buildings. Certainly the informality, spontaneity and full participation would have been lost as the church went to structured formal services.