Other Considerations

300 to 309 AD
The Maya develop the day-count calendar, which combines the 365-day Olmec calendar that has a 52-year cycle with the 260-day cycle known as the tzolkin, which has 13 cycles of 20 days each; this calendar dates events back to 3000 BC

330 to 339 AD
In 330 Constantinople is founded by Constantine I

390 to 399
The Roman emperor Theodosius closes the pagan temples in 392, effectively making Christianity the official religion of the Roman empire