Take a look at the Introit for tomorrow, the 13th Sunday after Pentecost. When we were in school, we would have gotten in trouble if we wrote “xiiii” as Roman Numerals instead of “xiv”—but you can see this was actually quite common.
“A much greater source of anxiety to Us is the style of action of those who maintain that liturgical worship should shed its sacred character, who foolishly say we should substitute for sacred items & furnishings ordinary common things in daily use.” —Pope Saint Paul VI (14 Oct 1968)