Gregorian Calendar What Purpose Does It Serve. Historians use the gregorian calendar because it has been employed by most nations since the 16th and 17th centuries. Two major players in our calendar history are the julian and gregorian calendars.
The gregorian calendar is a solar dating system used by most of the world. The gregorian calendar is internationally the most widely used civil calendar, and has been providing us with a dependable means of determining the date since its introduction.