The English names of the months are derived from Latin, the language of the Roman Empire and the lingua franca in Europe for more than fifteen centuries. If you have some knowledge of Latin or Romance languages, have you ever wondered why September, October, November, and December are the ninth, tenth, eleventh, and twelfth months respectively? Probably you may have thought these words are odd, since semantically they mean the seventh, eighth, ninth, and tenth months. Furthermore, why does August have 31 days, changing the pattern of odd-and-even numbers established in the previous months? The answers have to do with Julius Caesar.
Up to the height of Julius Caesar’s power and splendors, the Romans had been using a lunar calendar that divided a year into only ten months: 1) Martius (March), the month of Mars, who was the Roman god of war; 2) Aprilis (April), the month of opening, when the womb of nature opens with new life, as aperire means “to open” in Latin; 3) Maius (May), the month of Maia, who was the goddess of growth; 4) Junius (June), the month of youth, as juvenis means “young” in Latin; 5) Quintilis, the fifth month, as quinque means “five” in Latin; 6) Sextilis, the sixth month, as sex means “six” in Latin; 7) September, the seventh month, as septem means “seven” in Latin; October, the eighth month, as octo means “eight” in Latin; 9) November, the ninth month, as novem means “nine” in Latin; 10) December, the tenth month, as decem means “ten” in Latin.
After Julius Caesar conquered Egypt in 48 BC, he acquired a solar calendar - Aristarchus’s calendar of 239 BC - from the Alexandrian astronomer Sosigenes. More accurate than its Roman counterpart, this calendar was adopted by Caesar in 46 BC. It came to be known as the Julian Calendar, which had two months added at the beginning of a year: Januarius (January), the month of Janus, the Roman deity who had two faces and could look back to the year past and forward on the current year; and Februarius (February), the month of purification, as Februaorum was the Roman festival of purification and expiation.
Although these two months disrupted the order and made the fifth month the seventh, the sixth month the eighth, and so on, since people had been accustomed to the names of the ten months, the names remained unchanged. Quintilis, Sextilis, September, October, November, and December then became the seventh, eighth, ninth, eleventh, and twelfth months respectively, and they must have sounded misplaced, but this is only one of many examples of the inertia of language. Back then, Sextilis, the eighth month, had 30 days, and Februarius, the second month, had 29 days, except in each leap year when it had 30 days.
The names of the months seemed to be settled, but only two years later, Julius Caesar was assassinated. Mark Anthony became the most powerful man in Rome after defeating Marcus Brutus, one of the assassins and the conspirators. In honor of Julius Caesar as well as to stabilize his own power, he renamed Quintilis Julius, from which the English word July is derived. Then the course of history took a turn. Anthony stayed too long in Egypt, indulging in amorous pursuits with Cleopatra, and was defeated by Augustus Caesar, Julius Caesar’s grandnephew, who became the first Roman Emperor and, in a worldly sense, perhaps the greatest ruler of the Roman Empire. In honor of himself, he renamed Sextilis Augustus (August), because that was his "lucky month" in which he began his first Consulship, celebrated three Triumphs, and ended the Civil War, among some other military deeds. The only shortcoming was that the month had only 30 days. Then he took one day from Februarius and put it into Augustus, so that he would not be regarded as inferior to his granduncle, Julius Caesar. It was also to show his benevolence because February was the month when the Romans purified themselves by sacrificing animals as well as human lives. One day fewer possibly meant a few men saved.
This is the origin of the English names of the months, five of which are not what they mean semantically. Two months in a row have 31 days each, breaking the original pattern, and one month is much shorter than the others. Julius Caesar’s adoption of the solar calendar is a great contribution to our civilization, but his name was used by and compared with other politicians for their own power and fame. As a result, his name is remembered along with July. However, the name that should have been remembered with glory but has been forgotten is the creator of the calendar, the Greek mathematician and astronomer—Aristarchus.