https://nycschoolcalendar.net/The Roman calendar was reformed by means of Julius Caesar in 45 BC. The Julian calendar become now not depending on the commentary of the brand new moon however really accompanied an set of rules of introducing a soar day every 4 years. This created a dissociation of the calendar month from the lunation.
https://diyprintablecalendar.com/The Islamic calendar is based totally on the prohibition of intercalation (nasi') by using Muhammad, in Islamic tradition dated to a sermon held on nine Dhu al-Hijjah AH 10 (Julian date: 6 March 632). This led to an observation-primarily based lunar calendar that shifts relative to the seasons of the solar year.
the primary calendar reform of the early contemporary technology became the Gregorian calendar, brought in 1582 primarily based at the statement of an extended-term shift between the Julian calendar and the sun yr.
https://schulferienkalender.net/There have been a number of present day proposals for reform of the calendar, consisting of the sector Calendar, global constant Calendar, Holocene calendar, and, lately, the Hanke-Henry everlasting Calendar.