This section is from the "The New Student's Reference Work Volume 5: How And Why Stories" by Elinor Atkinson.
Four of the months aren't named. They just have numbers, but as the numbers are given in Latin, and Latin is a dead and by-gone language, their numbers pass for names, and few people are any the wiser. But we'll begin with the first one that has a name, and that's the very first month—January. That's such a good name it couldn't possibly be improved upon. The month was named for the old Roman god—Janus, the god of beginnings and endings. In statues Janus is represented with two faces. One face looks to the past, the other to the future. January first is New Year's day. Then we pay old debts and make new resolutions We ring the old year out, the new one in.
The name February comes from a festival of purification called Februa, in honor of a god. February, in Roman cities, was the month for the cleansing of temples and houses. It has lost its meaning with us, for February is far too cold for house cleaning. March is from Mars, the war god—a noisy, blustering month with storms and wind and cold that conquer the earth over again, year after year. That's a good name, too. April comes from "aperit," a Latin word that means "open." April is the opener of the gates of birth. Her coming means the renewal of life on the earth—the awakening of the earth from winter sleep, and recovery from the wounds of wars. May is from Maia, a goddess. She was a daughter of Atlas, the god who held the earth up on his shoulders. Maia was the mother of Mercury, the messenger god who, with wings on his heels, ran errands between earth and heaven. Special honor was paid to Maia for having such a son. She, with her six sisters, was set up in the sky and turned into the seven stars that form the Pleiades; and the lovely month of May was named for her. June was named for Juno, the proud wife of the great god Jupiter.
Beginning with July the months were numbered, until two very powerful Roman emperors ruled over most of the known world. These were Julius Caesar and Augustus Caesar. Their names were given to July and August. Belief in the old pagan gods died out, and no man after the Caesars was thought great enough to be allowed to claim a month for his own. So the old numbers still stand. They are septem—seven; octem—eight; novem—nine; decem—ten. This is odd, for today these are not the seventh, eighth, ninth and tenth months but the ninth, tenth, eleventh and twelfth. When they were numbered, however, the year began with March instead of with January. So these names are not only numbers, they are the wrong numbers. But do you think we are ever likely to change them?