Old Earth calendar
The old Earth calendar was an Earth calendar used for dates prior to the 24th century. 

In 2268, James T. Kirk requested that Doctor Leonard McCoy be outfitted like a Gestapo doctor from Nazi Germany with the rank of colonel, circa old Earth date 1944. This was done so that he could infiltrate Ekos. ()

's computer placed the years 2123 and 2190 on this calendar as well. ()

Time measurements
Culture