Sextilis or mensis Sextilis was the Latin name for what was originally the sixth month in the Roman calendar, when March was the first of ten months in the year. After the calendar reform that produced a twelve-month year, Sextilis became the eighth month, but retained its name. It was renamed Augustus (August) in 8 BC in honor of the first Roman emperor, Augustus. Sextilis followed Quinctilis, which was renamed Julius (July) after Julius Caesar, and preceded September, which was originally the seventh month.