After visiting numerous churches in
I discovered it is in fact a Latin phrase, deo optimum maximo, meaning “to the greatest and best God.” The phrase dates back to the era when Roman’s were polytheist. The phrase originally referred to Jove, who was the patron deity of the Roman state.
Centuries later the revered phrase was still used. However, through the adoption of Christianity the Romans became monotheists and the honorable phrase no longer referred to Jove. Rather, to the Christian God meaning, “to God, most good, most great.”
Therefore, the phrase is commonly found on Renaissance-era churches. Thus explaining why it is so common in Italian churches. So, if you get a chance to go to an Italian church keep your eyes out for the abbreviation D.O.M!