These now cherished Christmas traditions have a surprising history. It involves paganism.

It's the most wonderful time of the year.

And according to historians, this time of the year − known for lights, celebration and feasts − has been full of wonder and joy since long before Christians began observing Christmas to commemorate the birth of Jesus.

Many Christmastime traditions have their origins in wintertime traditions more broadly, specifically winter solstice celebrations ancient Romans and other pre-Christian people celebrated to mark the changing of the seasons.

Throughout history, the winter solstice − the shortest day and longest night of the year − has been commemorated with light-filled festivities, to remind us that the dreary, cold depths of winter don't last forever, said Brent Landau, a religion professor at the University of Texas at Austin who teaches a class called History of Christmas.

"The human impulse to mark or commemorate the passing of the seasons in general and the winter solstice in particular is extremely ancient," Landau told USA TODAY.

More than 2,000 years after the birth of Jesus, the history of quintessentially Christmas traditions and holiday items can be traced back to pre-Christian practices and culture, also referred to as paganism.

Here is a round-up of common Christmastime traditions that have their origins in pre-Christian religions, according to historians.

December 25th

The timing of Christmas likely evolved from when pre-Christian Europeans celebrated the winter solstice in late December, said Landau.

These days, Christmas roughly coincides with the winter solstice on Dec. 21.

In ancient Rome, when people used a different version of the calendar, called the Julian calendar, the winter solstice fell on Dec. 25 - so the two holidays were on the same day at one point in history.

"The connection between the birth of Jesus and the winter solstice in the ancient world was even more in your face and obvious," Landau said. "Like, it's the same day."

Ancient Romans also celebrated their sun god, Sol Invictus, on Dec. 25, according to Landau, because the winter solstice marked the real sun's annual rebirth from fading during fall and winter to being in the sky longer during spring and summer.

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Evergreen trees

Pre-Christian people's worship of nature, where many of their gods resided, can be directly linked to the dominant practice of decorating Christmas trees this time of year, according to Landau.

In ancient Rome, celebrating the winter solstice included adorning buildings and temples with evergreen plants, including evergreen trees, holly, mistletoe and ivy, Landau said. The evergreen plants and their red berries that come at wintertime are likely the main reason green and red are considered Christmas colors, he said.

The plants, which stay green through the winter, were "a reminder when everything is brown and dead that you've got this survival and this persistence throughout the coldest times of the year."

Ancient Druids, people who were in Britain, Ireland and part of modern France before Christ, saw mistletoe as a magical sign of life because it could bloom in the middle of winter. They would give it to both humans and animals in the hopes of restoring fertility.

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In ancient times, the evergreen tree "was certainly very symbolic to them probably in the same way that lots of folks, when they put that Christmas tree up, it really lifts their spirits," Landau said.

After Christianity began spreading through Europe, Pope Gregory in the year 601 told Christian missionaries that pagan practices, including using trees in ceremonies, could be continued as long as the items were "consecrated" to Christ, Oxford University Press says.

Later, in the 1600s, Christians in Germany were documented bringing evergreen trees inside their homes and calling them Christmas trees, according to Landau.

Today, we still decorate trees with lights as a way to brighten our homes and other spaces during the darkest time of year, Landau said.

Wreaths

Wreaths were featured in ancient Roman celebrations of Saturnalia, a mid-December holiday celebrating the agriculture god, Saturn.

Circle of holly branches were also likely part of winter solstice celebrations, Landau said.

"The imagery of the circle is particularly prevalent because by marking the winter solstice, you're saying, 'OK, this is a cyclical process that we go through every year and it gets really dark, and it gets really cold, but it doesn't last,'" he said.

Wassailing

Going from house to house and singing, or otherwise entertaining your neighbors, has a long history connecting back to ancient English and Norse customs.

In pre-Christian traditions, wassailing meant drinking hot alcoholic beverages and parading through an orchard to fend off bad spirits and ensure a good harvest, according to National Trust UK, a historical preservation society.

The word wassail comes from the Old Norse ves heill, which means to drink to good health.

By early modern times, wassailing was still a very alcohol-heavy, raucous activity, according to researchers including Stephen Nissenbaum, who wrote a book called "The Battle for Christmas."

Wintertime has long been when extra grain from fall harvests is turned into beer and liquor, Landau said, so wassailing included heavy drinking that was otherwise connected to this particular time of year.

"If you went to New York City in 1810 and wanted to see how Christmas was being celebrated, you'd probably be a little horrified because essentially, you'd have groups of young men who were just getting totally blitzed" going from house to house, demanding wealthier neighbors give them sweet treats, he said.

Today, we still sing the Christmas songs "Here We Come A-Wassailing," or "Here We Come A-Caroling," and organize actual caroling outings. The present tradition of caroling is much more tame, largely because Protestantism tamed it and made it much more children-centered, Landau said.

Yule log

The modern definition of yule, according to Merriam-Webster, is the feast of the nativity of Jesus Christ − or Christmas. Before the word took on its current meaning, yule was a pagan midwinter festival, the dictionary says.

In French and English Christmastime traditions, a special log called the yule log is brought in from outside and burned in the fireplace or on the hearth, according to the book "Christmas customs and traditions, their history and significance," which is required reading in Landau's college class.

The yule log provided welcome warmth during the winter and some also considered it to have "occult, magical properties," says the book, which was written by Clement A. Miles and published in 1912.

Some people who burnt a yule log kept it or its charcoal for the rest of the year because they thought it protected their house from lightning and their children from disease, according to Miles' research. The log's remains could also help cows give birth and keep crops healthy, the book says.

Today, the tradition of the wooden yule log has also been transformed into a popular Christmas dessert with the same name.

Contributing: Janet Loehrke, USA TODAY