In the 12 months 1582, Pope Gregory XIII decreed that there must be a trade in the Julian calendar. The Gregorian calendar become a theoretical calendar, and it was produced from very particular calculations of vernal equinoxes. The Julian calendar changed into based on the belief that the length between vernal equinoxes is 365 ¼ days, however in reality, it's far approximate ly eleven mins less. As such, the Gregorian calendar had three leap days removed each four hundred years. additionally, changes have been made to the lunar cycle, which helped within the calculation of Easter. Many eu countries did now not undertake the Gregorian calendar when it became brought, especially due to the Protestant Reformation that turned into taking vicinity at that point. nevertheless, by using the twentieth century, the calendar became the same old calendar in Europe. these days, it's miles the most widely used calendar inside the international.

“on the 12th day of Christmas …”

In 567 A.D., the Council of excursions ended a dispute. Western Europe celebrated the birth of Christ on Christmas Day, Dec. 25, because the holiest day of the season. eastern Europe celebrated Jan. 6, Epiphany, that's a Greek phrase which means “look” or “manifestation.” additionally known as 3 Kings Day, it recalled the visit of the smart men to Jesus in the manger – his “manifestation” to the Gentiles, as foretold in Isaiah forty nine:6: “i'm able to also give thee for a mild to the Gentiles, that thou mayest be my salvation unto the stop of the earth.”.https://howtowiki.net/january-calendar/.
https://calendardiy.com/december-calendar.html

Similarly, Epiphany commemorates Jesus’ baptism in the Jordan River, as recorded in John 1:29-34: “the next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world … that he have to be made manifest to Israel. … And John bare report, announcing … He that despatched me … said … Upon whom thou shalt see the Spirit descending, and remaining on him, the same is he which baptizeth with the Holy Ghost. and i noticed, and bare record that that is the Son of God.”