Antique circa 1919 lapel button made of bronze or brass motto of the Fifth Maryland National Guard Regiment, online Decus Et Praesidium

online Though I don't have any evidence to support it I believe this lapel button was likely something given to Veterans of the Fifth Regiment of the Maryland National Guard who are the 7th oldest active Regiment in the history of the United States Army dating back to 1774. They have been activated for virtually every war since that time though they have changed their destination to the 175th Infantry Regiment since 1939 so that helps to date this to likely post WWI. I have not been able to find another example. Measures 3/4"