when was the calendar created?
King Romulus. The original Roman calendar was said to be invented by Romulus, the first king of Rome, at around 753 BCE (Before Common Era). The calendar started the year in March (Martius) and consisted of 10 months, with 6 months of 30 days and 4 months of 31 days. The winter season was not assigned to any month, so the calendar year only lasted 304 days with 61 days unaccounted for in the winter.