Christianity Today highlights an except from the First Apology, a book written by Justin Martyr in 155 A.D. The excerpt describes Christian worship, and I was surprised and heartened by the familiarity. The entire book is online at Christian Classics Ethereal Library.
How the Early Christians Worshipped via Christianity Today
Excerpt of an excerpt:
And on the day called Sunday there is a meeting in one place of those who live in cities or the country, and the memoirs of the apostles or the writings of the prophets are read as long as time permits. When the reader has finished, the president in a discourse urges and invites [us] to the imitation of these noble things. Then we all stand up together and offer prayers. And, as said before, when we have finished the prayer, bread is brought, and wine and water, and the president similarly sends up prayers and thanksgivings to the best of his ability, and the congregation assents, saying the Amen; the distribution, and reception of the consecrated [elements] by each one, takes place and they are sent to the absent by the deacons.