September begins on the same day of the week as December every year, because there are 91 days separating September and December, which is a multiple of seven (the number of days in the week). No other month ends on the same day of the week as September in any year. September (from Latin septem, "seven") was originally the seventh of ten months on the oldest known Roman calendar, with March (Latin Martius) the first month of the year until perhaps as late as 153 BC. After the calendar reform that added January and February to the beginning of the year, September became the ninth month, but retained its name. It had 29 days until the Julian reform, which added a day. September's birthstone is the sapphire. The Zodiac signs for individuals born in this month are Virgo (until September 21) and Libra (from September 22 onward). The flowers are the forget-me-not, morning glory, and aster
