One problem with cataloging coins in a database is that the coins of the world use different date systems. The World Coin Database is making an attempt to be as accurate as possible by storing dates in the coin's native date system. The majority of coins use the Gregorian calendar, but some use date systems that do no equate directly to a Gregorian year. Below is a list of guides that will help you decipher any non-Latin date characters and convert to a Gregorian date. More countries will be added as time goes on, and feel free to contact me with any suggestions. You may also want to visit the Creounity Time Machine for interactive coin date system converters.