Calculate dates based on regnal years

Dates based on regnal years refer to the year of the current monarch’s reign and usually have the format “year + monarch” (e.g. “4 Mary”).  This page will take a date in regnal years and return an ordinary date. For instance, if you enter 6/1 1 Elizabeth I, you will get the year 1559 because June 1st in her first regnal year occurred in 1559.