comes from the Latin root septem-, meaning “seven,” because in the original Roman republican calendar September was the seventh month of the year rather than the ninth. The Roman calendar was only ten months long and included the following months—Martius, Aprilis, Maius, Junius, Quintilis, Sextilis, September, October, November, and December. The last six months were assigned names according to their ordinal numbers—Quintilis is the fifth month, Sextilis is the sixth month, and so on.