The old resurrection theory for Sunday worship may well be an early root. Resurrection, though, was not a commonly held pre-catholic notion. Only when the first council of bishops outlawed various diverse early Christian belief systems and those gospels that didn't make the Nicean cut, calling them 'heretical' and ordering their elimination, was there a consensus.
And Jack's fun comment might merit more consideration: the Roman Empire had no beef with any pagan religion and -- because many (not only the popular Sol Invictus) incorporated sun worship -- I guess Sunday was a pretty quiet and convenient day for those new Christians who would hitherto have been spending it in the worship of their former gods and mowing the lawn.
Constantine and his bishops certainly saw the value of incorporating older established religious traditions like this into the new. Christian missionaries continued the policy of assimilation, of course, wherever they wanted to make converts of those holding older religious beliefs, which is why so many annual Christian festivals also coincide with those of older faiths. They appealed to tradition.
Best. Neil
Absolutely. The 'hand over' would have been made to appear as seam-less as possible. The surprise is that so many years later, the deception remains intact - ludicrous.
In Exodus the command is to never create any type of image to bow down to. 'Catholics' who before they 'joined up', like all backward tribes, used to enjoy a bit of bowing down to statues, were allowed to continue,despite 'God's word' , just to keep them happy and onside. They now even had a few 'saints' to worship, even the lovely Mary. When a religion, from it's very conception, allows such contradictions, (and they all contain them) is it any wonder that it's all one collossal mess now and makes it's followers look stupid? Rightly so, IMO.