A church building is a building or structure whose primary purpose is to facilitate the meeting of a church. Originally, Christians met in synagogues and in one another's homes. As Christianity grew and became more accepted by governments, rooms, and eventually entire buildings, were set aside for the explicit purpose of Christian worship.
Traditional church buildings are often in the shape of a cross, and frequently have a tower or dome. More modern church buildings have a variety of architectural styles and layouts; many buildings that were designed for other purposes have now been converted for church use, and similarly many original church buildings have been put to other uses.
The first Christians were, like Jesus, Jews resident in Israel who worshiped on occasion in the Temple in Jerusalem and weekly in local synagogues. Temple worship was a ritual involving sacrifice, occasionally including the sacrifice of animals in atonement for sin, offered to Yahweh until Jesus became the final sacrificial offering on Calvary. The New Testament includes many references to Jesus visiting the Temple, the first time as an infant with his parents.
The early history of the synagogue is obscure, but it seems to be an institution developed for public Jewish worship during the Babylonian captivity when the Jews did not have access to the Jerusalem Temple for ritual sacrifice. Instead, they developed a daily and weekly service of readings from the Torah or the prophets followed by commentary. This could be carried out in a house if the attendance was small enough, and in many towns of the Diaspora that was the case. In others, more elaborate architectural settings developed, sometimes by converting a house and sometimes by converting a previously public building. The minimum requirements seem to have been a meeting room with adequate seating, a case for the Torah scrolls, and a raised platform for the reader and preacher.
Jesus himself participated in this sort of service as a reader and commentator (see Gospel of Luke 4: 16-24) and his followers probably remained worshipers in synagogues in some cities. However, following the destruction of the Temple in Jerusalem in 70, the new Christian movement and Judaism increasingly parted ways. The Church became overwhelmingly Gentile sometime in the 4th century.
The Syrian city of Dura-Europos on the West bank of the Euphrates was an outpost town between the Roman and Parthian empires. During a siege by Parthian troops in A.D. 257 the buildings in the outermost blocks of the city grid were partially destroyed and filled with rubble to reinforce the city wall. Thus were preserved and securely dated the earliest decorated church and a synagogue decorated with extensive wall paintings. Both had been converted from earlier private buildings.
The church at Dura Europos has a special room dedicated for baptisms with a large baptismal font.
After the Roman Empire became officially Christian, the term came by extension to refer to a large and important church that has been given special ceremonial rites by the Pope. Thus the word retains two senses today, one architectural and the other ecclesiastical.
A cathedral is a church, usually Roman Catholic, Anglican, or Eastern Orthodox, housing the seat of a bishop. The word cathedral takes its name from the word cathedra, or Bishop's Throne (In Latin: ecclesia cathedralis). The term is sometimes (improperly) used to refer to any church of great size.
The church that has the function of cathedral is not of necessity a large building. It might be as small as Christ Church Cathedral, Oxford or Chur Cathedral, Switzerland. But frequently, the cathedral, along with some of the abbey churches, was the largest building in any region.
Old and disused Church buildings can be seen as an interesting proposition for developers as the architecture and location often provide for attractive homes or city centre entertainment venues On the other hand, many newer Churches have decided to host meetings in public buildings such as schools, universities , cinemas or theatres.
There is another trend to convert old buildings for worship use rather than face the construction costs and planning difficulties of a new build. Unusual venues in the UK include an old Tram power station , a former bus garage , an old cinema and bingo hall , a former Territorial Army Drill Hall, a former synagogue and a windmill.