For example , the mythical creation date in the Maya calendar is August 11 , 3114 BC in the proleptic Gregorian calendar and September 6 , - 3113 astronomical .
Proleptic Gregorian dates vary substantially from astronomical dates .
The mythical creation date in the Maya calendar is August 11 , 3114 BC in the proleptic Gregorian calendar and September 6 , - 3113 astronomical .
Proleptic Gregorian dates vary substantially from astronomical dates .