So here we go with ‘Numbers” month (including numerals 🙂 )

Methods of timekeeping can be reconstructed for the prehistoric period from at least the Neolithic. The natural units for timekeeping used by most historical societies are the day, the solar year and the lunation. Calendars are explicit schemes used for timekeeping. The first recorded calendars date to the Bronze Age, based on the development of writing in the Ancient Near East, the Egyptian and Sumerian calendars. A larger number of calendar systems of the Ancient Near East becomes accessible in the Iron Age, based on the Babylonian calendar. This includes the calendar of the Persian Empire, which in turn gave rise to the Zoroastrian calendar as well as the Hebrew calendar.

A great number of Hellenic calendars develop in Classical Greece, and with the Hellenistic period also influence calendars outside of the immediate sphere of Greek influence, giving rise to the various Hindu calendars as well as to the ancient Roman calendar.

Calendars in antiquity were usually lunisolar, depending on the introduction of intercalary months to align the solar and the lunar years. This was mostly based on observation, but there may have been early attempts to model the pattern of intercalation algorithmically, as evidenced in the fragmentary 2nd-century Coligny calendar. Nevertheless, the Roman calendar contained very ancient remnants of a pre-Etruscan 10-month solar year.

The Roman calendar was reformed by Julius Caesar in 45 BCE. The Julian calendar was no longer dependent on the observation of the new moon but simply followed an algorithm of introducing a leap day every four years. This created a dissociation of the calendar month from the lunation. The Gregorian calendar was introduced as a refinement of the Julian calendar in 1582 and is today in worldwide use as the de facto calendar for secular purposes.

Calendars usually print the date using cardinal numbers, one, two, three and so on, but we say the date using ordinal numbers, first, second, third etc.