By LUIS ANDRES HENAO, Associated Press

Christmas, a celebration recognized worldwide, marks the birth of Jesus Christ. However, many may be surprised to learn that the earliest Christians did not observe his birth each year. Instead, they focused more on the celebration of Easter, which commemorates Jesus’ resurrection. Interestingly, the figure of Santa Claus that we know today was inspired by a generous fourth-century Christian saint. Additionally, a fascinating modern tradition in Japan involves feasting on Kentucky Fried Chicken as part of their Christmas celebrations.

Since the dawn of the 20th century, Christmas has transformed from a primarily religious observance into a widely celebrated cultural holiday. It is embraced by both Christians and non-Christians alike around the world. During the festive season, families come together to exchange gifts and cards, and to decorate their homes with Christmas trees, a tradition beloved by many.

Let’s delve into the history, beliefs, and evolution of this beloved holiday:

Origins and early history of Christmas

In the early days, Jesus’ followers did not mark his birth annually. Their primary focus was on Easter, which holds a central place in Christian beliefs as it honors Jesus’ resurrection.

When it comes to the nativity story, it is detailed in only two of the four Gospels in the New Testament: Matthew and Luke. Each account offers unique details, but both concur that Bethlehem was the birthplace of Jesus.

The exact day, month and even year of Jesus’s birth are unknown, said Christine Shepardson, a professor at the University of Tennessee who studies early Christianity.

The tradition of celebrating Jesus’ birth on Dec. 25, she said, only emerged in the fourth century.

“It’s hard to overemphasize how important the fourth century is for constructing Christianity as we experience it in our world today,” Shepardson said. It was then, under Emperor Constantine, that Christians began the practice of gathering at churches instead of meeting at homes.

Some theories say the date coincides with existing pagan winter solstice festivals, including the Roman celebration of Sol Invictus, or the “Unconquered Sun,” on Dec 25.

While most Christians celebrate Christmas on Dec. 25, some Eastern Orthodox traditions celebrate the holy day on Jan. 7. That’s because they follow the ancient Julian calendar, which runs 13 days behind the Gregorian calendar, used by Catholic and Protestant churches as well as by much of the secular world.

Rowdy medieval celebrations

For centuries, especially during the Middle Ages, Christmas was associated with rowdy street celebrations of feasting and drinking, and for many Christians, it “was not in good standing as a holiday,” said Thomas Ruys Smith, a professor of American literature and culture at the University of East Anglia in England.

“Puritans,” he said, “were not fond of Christmas.”

But in the 19th century, he said, Christmas became “respectable” with “the domestic celebration that we understand today — one centered around the home, the family, children, gift-giving.”

The roots of modern-day Christmas can be traced back to Germany. In the late 19th century, there are accounts of Christmas trees and gift-giving that, according to Smith, later spread to Britain and America, helping to revitalize Christmas on both sides of the Atlantic.

Christmas became further popularized with the publication of “A Christmas Carol” by Charles Dickens in 1843, and the writings of Washington Irving, who was a fan of St. Nicholas and helped popularize the celebration of Christmas in America.

The first Rockefeller Center Christmas tree was put up by workers in 1931 to raise spirits during the Great Depression. The tradition stuck as the first tree-lighting ceremony was held in 1933 and remains one of New York City’s most popular holiday attractions.

America’s secular Santa is inspired by a Christian saint

St. Nicholas was a fourth-century Christian bishop from the Mediterranean port city of Myra (in modern-day Turkey). His acts of generosity inspired the secular Santa Claus legend.

The legends surrounding jolly old St. Nicholas — celebrated annually on Dec. 6 — go way beyond delivering candy and toys to children. He is believed to have interceded on behalf of wrongly condemned prisoners and miraculously saved sailors from storms.

Devotion to St. Nicholas spread during the Middle Ages across Europe and he became a favorite subject for medieval artists and liturgical plays. He is the patron saint of sailors and children, as well as of Greece, Russia and New York.

Devotion to St. Nicholas seems to have faded after the 16th century Protestant Reformation, except in the Netherlands, where his legend remained as Sinterklaas. In the 17th century, Dutch Protestants who settled in New York brought the Sinterklaas tradition with them.

Eventually, St. Nicholas morphed into the secular Santa Claus.

It’s not just Santa who delivers the gifts

In the U.K., it’s Father Christmas; in Greece and Cyprus, St. Basil (who arrives on New Year’s Eve). In some parts of Italy, it’s St. Lucy (earlier in December) and in other Italian regions, Befana, a witch-like figure, who brings presents on the Epiphany on Jan. 6.

Instead of a friendly Santa Claus, children in Iceland enjoy favors from 13 mischievous troll brothers, called the Yule Lads. They come down from their mountain cave 13 days before Christmas, according to folklore.

Christian traditions of Christmas

One of the oldest traditions around Christmas is bringing greenery — holly, ivy or evergreen trees — into homes. But determining whether it’s a Christian tradition is harder. “For many people, the evergreen can symbolize Christ’s promise of eternal life and his return from death,” Smith said. “So, you can interpret that evergreen tradition within the Christian concept.”

The decorating of evergreen trees is a German custom that began in the 16th century, said Maria Kennedy, a professor at Rutgers University—New Brunswick’s  Department of American Studies. It was later popularized in England and America.

“Mistletoe, an evergreen shrub, was used in celebrations dating back to the ancient Druids — Celtic religious leaders — some 2,000 years ago,” Kennedy writes in The Surprising History of Christmas Traditions.