What did the earliest Christians actually do?

The Didache is a short handbook of instructions, and it reads like one. On baptism: do it in running water, "but if you have not living water, baptize into other water; and if you can not in cold, in warm", and if neither, pour water three times over the head. On fasting: not on the days the hypocrites use, but on Wednesday and Friday. On prayer: here is the Lord’s Prayer, three times a day.

The tone is the evidence. Nobody writes rules about which temperature of water will do unless real people are standing in front of them with the wrong kind of water.

Around 155, Justin wrote to Antoninus Pius to explain what Christians were, and included an account of a Sunday meeting so plain it could be a set of minutes. Everyone in the city and countryside gathers in one place. The memoirs of the apostles or the writings of the prophets are read "as long as time permits". The president speaks, everyone stands and prays, bread and wine and water are brought, the people answer Amen, and deacons carry a portion to those who could not come.

Then the collection: those who are willing give what they think fit, and it is kept by the president, "who succours the orphans and widows and those who, through sickness or any other cause, are in want".

Justin is writing to persuade, so he is choosing what to say. He is not free to invent it, because he is describing a practice his readers could have investigated and were in some cases already prosecuting.

Around 112, Pliny the Younger told the emperor Trajan what he had established about the Christians in his province, partly by torturing two enslaved women who were called deacons. They met before dawn on a fixed day, sang a hymn to Christ as to a god, and bound themselves by oath, not to any crime, but not to commit theft or robbery or adultery, not to break their word, and not to refuse to return a deposit. Then they separated and came back later for a meal, which he notes was ordinary food.

Where it overlaps with Justin’s account, written some forty years later, it agrees: a fixed day, and a meal. It comes from a man who was executing the people he was describing and concluded it was all a depraved and excessive superstition.

The Didache devotes a chapter to travelling apostles and prophets, and the instructions are not pious. Receive them as the Lord. But if one stays more than two days, or asks for money, he is a false prophet.

That is a document written by people who had met the other kind. A true prophet who settled among them was another matter, and was to be given the firstfruits.

Three documents, one from Bithynia, one by a teacher who lived in Rome and one whose place of origin is disputed, are still three points. Paul Bradshaw’s study of the origins of Christian worship gives up fitting the evidence into one line of development from the apostles to the fourth century, and reads the variety in the sources as the real picture. The Didache’s own fussiness about method points the same way.

What the agreement establishes is that a recognisable core existed early and travelled. It does not establish that every congregation did it this way.

All three sources describe eating together, and none of them uses the language of substance in which later churches defined, and divided over, what is happening when they do. Justin says the bread and cup are received "not as common bread and common drink", and calls the food "the flesh and blood of that Jesus who was made flesh". The Didache’s thanksgiving prayers say strikingly little about it.

Reading a fourth-century or sixteenth-century definition back into these texts is an anachronism, in every direction.

The order of service survives. What does not is why people kept coming, in a context where doing so was illegal, socially costly and occasionally fatal. Every account of that was written by someone arguing a case.

The Catholic catechism reads the resemblance between Justin’s Sunday and its own as continuity: the basic lines of the celebration, it says, "have stayed the same until our own day for all the great liturgical families". Calvin measured the Supper by the apostolic church instead. He held that not long after the apostles "the Supper was tainted with adulteration", and wanted no meeting of the church without "the word, prayer, the dispensation of the Supper, and alms".

Both are using the early evidence as a measure. What the documents themselves show is a set of practices, recognisably continuous with what is done on a Sunday now, described by people who had no idea anyone would still be doing it.