Have you ever wondered why September (septem = seven in Latin), October (october = eight), November (novem = nine), December (decem = ten) are named after the Latin words for seven/eight/nine/ten yet are the ninth, tenth, eleventh and twelfth months in the calendar?
Turns out, March was the first month in the ancient Roman calendar, which would then make the above names accurate. But Julius Caesar added January and February, shifting the other ten months forward from their original position, but not changing the names. This Julian calendar was then refined by Pope Gregory XIII in the 1500s to be more aligned with the solar year, leading to the Gregorian calendar as we know it today.