American Christians are accustomed to celebrating Christmas on December 25, the date which today many believe commemorates the birth of Jesus.But in Israel, Christmas is celebrated on December 25, January 7 and January 19. Why?There are two different calendars, two different dates for celebration and three Churches.Dr. Sergio La Porta, Haig and Isabel Berberian Professor of Armenian Studies and interim associate dean of the College of Arts and Humanities at California State University in Fresno, explained to the Magazine that the Roman Catholic Church follows the Gregorian calendar, while the Armenian Church in Jerusalem and the Greek Orthodox Church follow what is known as the Julian calendar.Armenians in the rest of the world follow the Gregorian calendar, the calendar that was first instituted in 1582 by Pope Gregory XIII. Today, of course, the Gregorian calendar is the internationally accepted civil calendar and is also known as the Western, secular or Christian calendar.The Julian calendar is a dating system established by Julius Caesar.“They did this on purpose during the Ottoman period so that they would not overlap in their celebrations” at the Church of the Nativity, La Porta explained about the variant dates. “But it creates a lot of confusion – well, a lot of confusion for us.”The Roman Catholics celebrate on December 25. The Greek Orthodox Church celebrates on December 25, too, but on the Julian calendar, which is about 13 days off from the Gregorian calendar. December 25 falls on January 7 on the Julian calendar.The Armenian Church in Jerusalem celebrates Christmas on January 6 according to the Julian calendar, which winds up being January 19 on the Gregorian calendar.La Porta said Armenians celebrate the birth and the Epiphany – the day they believe that Jesus was revealed as God’s son – within the same two-day period, from January 5 to January 6 on the Julian calendar or from the afternoon of January 18 until midnight on January 19 on the Gregorian calendar. “This really helped in the Ottoman period,” La Porta said, referring to requiring the Armenians of Jerusalem to adhere to the Julian calendar while the rest of the Armenian world made the logical switch. “Otherwise, everyone would be going to the Church of the Nativity at the same time and there would have been fights. By making the Armenians stick to the Julian calendar, Christmas for them is about two weeks later. That really helps.”La Porta explained that Christmas began being celebrated on the 25th of December during the time of the Roman Emperor Constantine, who himself was a Christian. The Roman Empire likely chose that day because the winter solstice and the ancient pagan Roman midwinter festival Dies Natalis Solis Invicti or the Festival of the “Unconquered” Sun, were traditionally celebrated around that time. “Constantine would have moved nativity to the 25th to wipe out the memory of the sun holiday and also because people already celebrated things then, so it was a good time for a holiday,” La Porta said. “Most scholars think Jesus was born in the spring, but there are a lot of arguments.”However, as far as which calendar is more accurate, there is no argument. The Gregorian calendar is more accurate than the Julian calendar, which had too many days. In fact, when the switch was made from the Julian calendar to the Gregorian calendar in 1582, 10 days were lost. Christmas celebrations in Israel are slowly becoming more aligned with Western celebrations, including putting up Christmas trees and decorating with lights. But the holiday in the Holy Land still centers on liturgical worship in Bethlehem and communal feasting.A spokeswoman for the Armenian department of press and information for the Armenian Patriarchate told the Magazine about Christmas celebrations in Manger Square, where she said the voices of young choir singers and shouts of joy are accompanied by the sounds of trumpets, bagpipes and music. The Armenian community of Jerusalem is joined by Armenian worshipers from Jaffa, Haifa and Ramle, as well as pilgrims from Turkey, Armenia and the United States. The more serious worshipers pray midnight mass in the church, with a service that begins between 10 p.m. and 11 p.m. and ends only around 6 a.m. or 7 a.m. the next morning. Then, the spokeswoman said, the community gathers for special cakes, breads and sweets.“There is always food for everybody,” she said.