October (Roman month) October (Roman month) October (from Latin "octo", "eight") or mensis October was the eighth of ten months on the oldest Roman calendar. It had 31 days. October followed September (from "septem", "seven") and preceded November ("novem", "nine"). After the calendar reform that resulted in a 12-month year, October became the tenth month, but retained its numerical name, as did the other months from September through December. Some of the observances in October marked the close of the season for military campaigning and farming, which commenced in March ("Martius", "Mars' month"). October was under the guardianship "(tutela)" of Mars. The Romans
Adoption of the Gregorian calendar 1 for 1868, "Taishō" 1 for 1912, "Shōwa" 1 for 1926, "Heisei" 1 for 1989, and so on. Still, this system has increasingly been replaced in popular usage by the "Western calendar" (西暦, "seireki") over the course of the twentieth century. Korea adopted the Gregorian calendar on 1 January 1895 with the active participation of Yu Kil-chun. Although the new calendar continued to number its months, there were multiple systems used to refer to its years: during the Joseon Dynasty, in 1895–97, its years were numbered from the founding of that dynasty, regarding 1392 as year one; then between 1897