HI, Henrik —

All liturgies have undergone development. Ask your Coptic friends whether they still celebrate the  Liturgy of St. Mark [New Advent][Wikipedia] (their original Liturgy). They will probably cough and mumble under their breath (or maybe laugh as they did when I brought this up on my visit to a Coptic Orthodox church) because they don't.

What they celebrate is, what they call, the  Liturgy of St. Basil [New Advent][Wikipedia], and even if we assume this was done by St. Basil (chances are it has developed since then), that's still several hundred years after the Apostles.

Frequently, liturgy develops because it's too long. The Liturgy of St. Mark [New Advent][Wikipedia] is so long, it's only done in monasteries. As it is, their parish liturgy is three hours long. The Byzantine world started with the Liturgy of St. James, which was shortened into the Liturgy of St. Basil, (not the same as the Coptic liturgy of that name), which was further shortened into the Liturgy of St. John Chrysostom [EWTN][Wikipedia].

There are other reasons to change the liturgy, for example, to accentuate doctrinal points.
The term Mother of God may have entered during the (Arian and/or Nestorian) crises to emphasize Christ's nature. In the West, the Creed was changed to defend against Arianism as well. The Church's needs changes and the culture changes as well. It is an error to think that the way things were done in 33 A.D. is the way things should be done in 2011 A.D.

Let's also consider the fact that there has never been a uniform liturgy. Even if the Copts did follow the Liturgy of St. Mark [New Advent][Wikipedia]:

• the Syrians did a different liturgy
• the Armenians still another
• the Indians still another
• the Greeks have theirs, and
• so forth.

There is no one right liturgy; that implies that liturgy can vary or, put another way, develop and change.

The key is what is meant by very much like. There is a lot of play there. You can go back to liturgies in the first few centuries and see marked similarities between the modern Roman liturgy and the ancient one.

In fact, some ancient texts were restored in the reforms that followed Second Vatican Council. The fact is, there are similarities between the new Roman Liturgy and the ancient Roman Liturgy, and the Copts have developed their liturgy over 2,000 years, so the question is not whether liturgy can develop, but how much it should develop, which is a prudential question, not a doctrinal one, as long as you maintain the sacrificial/eucharistic aspect of it.

If this question continues to plague you, I'd recommend you obtain a copy of the Liturgy of St. Mark [New Advent][Wikipedia] and the Liturgy of St. Basil [New Advent][Wikipedia] (be sure you get the Coptic version).

Compare them to see exactly how very much like the new one is compared to the old one.
My suspicion is that even if you discount the couple of hours they excised from it, you'll find more of a patchwork than a touch up.

Eric