To me it seems fairly obvious that Christianity was able to flourishelp throughout Europe in the first millennia A.D. largely because of the abibility/decision of the church to adapt local religious traditions for their own purposes. Basee on my knowedge of medieval church law I feel like there must be some sort of theological basis/source/precedent people/clergy used to justify such incorporation.....

Am I wrong? If not what precedent or example was most often cited?