September (Roman month) was adjusted to September 1 in the 5th century to coincide with the tax year. September (Roman month) September (from Latin "septem", "seven") or mensis September was originally the seventh of ten months on the ancient Roman calendar that began with March ("mensis Martius", "Mars' month"). It had 29 days. After the reforms that resulted in a 12-month year, September became the ninth month, but retained its name. September followed what was originally Sextilis, the "sixth" month, renamed "Augustus" in honor of the first Roman emperor, and preceded October, the "eighth" month that like September retained its numerical name contrary
Adoption of the Gregorian calendar government in 1912 as the start rather than the regnal year of an emperor. The adopted calendar in both mainland China and Taiwan are called the "Public Calendar" (), or "New Calendar" (). Months in Gregorian calendar in Chinese are rarely named, instead they are usually numbered. For instance, Gregorian calendar December in China are usually written as month 12. On the other hand, in Chinese calendar, the 11th month and 12th month are usually nicknamed. Orally, people are accustomed to call the date in the month as "No. "dd"", for example, the Spring Festival of this year (2017) is