That Old Liturgical Latitudinarian, Pope St. Gregory the Great

"You know, my brother, the custom of the Roman church in which you remember you were trained. But if you have found anything in either the Roman or the Gallican or any other church which may be more acceptable to Almighty God, I am willing that you carefully make choice of the same and diligently teach the English church, which is as yet new in the faith, whatever you can gather from the several churches. For things are not to be loved for the sake of places but places for the sake of good things. Select, therefore, from every church the things that are devout religious and upright, and when you have, as it were, combined them into one body, let the minds of the English be trained therein." (to St. Augustine of Canterbury) in the Venerable Bede's Ecclesiastical History of the British Isles