Nuna Pompilus, the Roman ruler, added two extra months. January at the beggining and February at the end of the calendar to create a 12- month calendar. He also deducted one day from the 30- day months. A s a result of this they had 56 days to divide between January and February. Later, January was given an extra day. The Roman republican caôendar was introduced by the Etruscan Tarquinius Priscus ( 616-579 BCE), according to the tradition of the fifth king of Rome. Romulus, the founder of Rome, instituted the calendar in about 738 BCE. This dating system was probably a product of evolution from the Greek lunar calendar, which was derived from the Babylonian calendar. The months carried the names Martius, Aprilis, Maius, Juniius, Quintilis, Sextilis, September, October, November and December, - the lasr six names correspond to the Latin words for numbers 5 through 10. In 452 BCE, February was moved between January and March. IN 46 BCE, Julius Caesar initiated a detailed reform that resulted in the establishment of a new dating system, the Julian calendar. Roman republican calendar was carried over into the Gregorian calendar now in general use. The Romans did not have weekdays in the same sense of our Monday, Tuesday, ets., however they did have a defined markers within each month. Originally, the month and markers were based on the moon. At the time of their early kings, Roman months were of a lenght identical to the lunar cycle. Each month was divided into sections that ended on the day of one of the first three phases of the moon: new, first quarter or full. All days were referred to in terms of one of these three moon phase names, Kalends, Nones or Ides. At that tome a pontifex(priest) was assigned to observe the sky. When he first sighted a thin lunar crescent he called out that there was a new moon and declared the next month had started. For centuries afterward, Romans referred to the first day of each month a Kalendae or Kalends from the Latin word calare( to announce solemnly, to call out). The word calendar was derived from this custom.
A s mentioned above, the months of the Roman calendar contained three primary markers – The Kalends, the Nones and the Ides. The days were each identified with certain letters and names. The archaic form of the K, for Kalends, was used in front of the name of the month. The first letter was called the Nundinae ( nine day), or the Nundinal letter, and it represented the market day. Every ninth day was a market day.