by oggbashan
I don't think that the Roman church described itself as Catholic that far back.
A
Saint Ignatius used it first, c110CE. The use of it as Official dates from Theodosius I at the end of the 4th Century, a generation before the legions withdrew and a couple of hundred years before this. At least he didn't have to put up with Henry I's idea of Christmas merriment, Roland the Farter having a contract to perform a leap and a fart in the face of the King at the Christmas Feast. Roland's boss Rahere set up St Bart's hospital, which was evidently needed.