Based on readings from the web and books, this is a summary of how we came to have the current system of months.
Initially, the months were based on the waxing and waining of the moon. The early Greeks would watch for the first sliver of the new moon and call the next day the first day of the month. The first moon after the winter had passed was the first month of the year and was simply numbered "1." In that area, winter ended in about what we call Feburary now so the first month was what we now know as March. Each day of that month was counted until the moon had become full, then wained to nothing. The day after the moon reappeared was the first day of the second month and the counting of the days started over from one. After the 10th month, winter started again and as far as we can tell, the months were simply not recorded until the next spring. This had the advantage of letting the moon count out the months while avoiding the fact that the moon and the sun are not in sync. 12 lunar cycles are 354 days and a year is about 365.
Some of the months got renamed after gods so these 10 months became known as Martius (after the god Mars), Aprilis (goddess Aphrodite?), Maius (the goddess Maia), Junius (goddess Juno), Quintilis (5), Sextilis (6), September (7), October (8), November (9), and December(10).
This continued into early Rome but slowly became complex, messy and less connected to the moon. At one point the people in charge of the calender would change the number of days in a month just to get a politician out of office a bit early or keep them in office a bit longer. Julias Ceaser got fed up with it and standardized on the "Julian Calender" (not to be confused with Julian date or day numbering systems). His calender had two new months added to account for the winter: January and Feburary. These were named for the god Janus and a festival called Februa. He also changed the name of the original 5th month from Quintilis to Julius after himself. He also decided to start the year in January. This is why the 9th thru 12th months have names that mean 7th, 8th, 9th and 10th. Eemporor Augustus later renamed Sextillis after himself.
Since then the number of days in each month have been adjusted, but the months have stayed and retained more or less the same names.
| Now | Then | From |
|---|---|---|
| January | Januarius | god Janus (added by Caeser) |
| February | Februarius | festival Februa (added by Caeser) |
| March | Martius | god Mars / first month (end of winter) |
| April | Aprilis | god Aphrodite or maybe aperire, Latin for "to open" / two |
| May | Maius | god Maia / three |
| June | Junius | god Juno / four |
| July | Julius | emperor Julius Caesar Quintilis / five |
| August | Augustus | emperor Augustus Sextilis / six |
| September | September | septem, seven |
| October | October | octo, eight |
| November | November | novem, nine |
| December | December | decem, ten |
See also: