When did church start Sunday service? Why?

Apparently the Roman church started it.

NOT ONE of the texts I read, set the first day of the week, Sunday, apart as a rest day or as an more important than any other day of the week.

A better question remains then:

Why Sunday over Saturday?

Which is really the Sabbath?

The Sabbath is still Saturday according to all a study of the Greek Hebrew Word.

So another great question remains:

Are we Christians today in trouble (or in violation) for using Sunday as oppose to Saturday? Or is God just generally happy that we are keeping "a day" out of seven holy, restful, and "Sabbath?" Will God at least punish the Roman church?

Other sources:

Book and movie by David Pack


Final Thought:

Christ's resurrection was on Sunday, this is why Sunday was so important.

An opposing thoery or thought could be that, Saturday was God's "day of rest" therefor so it should also be ours.... (that assumes a 7-day Creation)...