The modern view of Christmas actually isn’t the same now as what it was to begin with. While the holiday is intended to celebrate the birth of Jesus, it is not actually his birthday. For starters, in fact, no one knows exactly when he was born.
The modern calendar, the Gregorian calendar, is based around the approximate birth of Jesus; meaning that Jesus was born 2,016 years ago and that 0 AD would be the year Jesus was born. Unfortunately, it seems that when the original date was being calculated, they mistranslated the Roman numerals and it should have been what is by modern calendars approximately 4 BC. More recently, some scholars have determined from various references in the Bible that Jesus was born between 7 – 5 BC.
Then there’s the day itself. Jesus was not born on December 25. The earliest mention of December 25 as Jesus’ “birthday” comes from a mid-fourth-century Roman almanac that lists the death dates of various Christian bishops and martyrs. The first date listed, December 25, is marked: natus Christus in Betleem Judeae: “Christ was born in Bethlehem of Judea.” Even looking at the setting of the story, things like the shepherds bringing their flocks in at night, dates between May and October have been suggested.
Even where Jesus was born is somewhat in question. The Gospels say Jesus was born in Bethlehem, yet Jesus is called “Jesus of Nazareth” throughout the rest of the New Testament. This small detail is causing scholars to question just where Jesus was actually born.
The term "Christmas" originated from the Catholic Church as “The Mass Of Christ” or more commonly “Christ’s Mass.” Christ’s Mass was eventually bastardized to become Christmas. The date of Christ’s Mass was placed on December 25 for two reasons. The vast majority of Catholic Christian holidays were responses to pagan holidays, primarily in an attempt to “overthrow” older religions and practices. The first reason Christ’s Mass was originally celebrated in December was to offset the pagan celebration of the winter solstice, also known as Yule. While we might then logically conclude that Christ’s Mass should also be on the winter solstice as well, the Catholic Church went a step further, which leads to the second reason. The ancients didn’t have watches, and clocks weren’t ubiquitous like they are now. As a result, they were more attuned to nature and the changes in the seasons. The 25th was chosen as the daylight hours were getting longer (they could more readily see that the daylight hours were getting longer immediately after the winter solstice) which came to represent the coming light of the Lord. Since not only many pagan religions also give presents during the winter celebrations, the story of the Magi in the book of Matthew (for example) also bringing gifts, that practice was also incorporated in the Christian celebration. The tradition that there were three wise men arose from the fact that the Bible mentions three gifts (see Matthew 2:11), but the Bible doesn’t ever actually say how many wise men made the journey to see the baby Jesus.
In fact, many of the other trappings of Christmas are either borne of older religions or are later additions from cultures that are also not Jewish. (Always remember that Jesus, whose name was in fact Yeshua, which translates to Joshua but was such a common name that it was later translated to Jesus to separate him, ignoring that the Hebrew alphabet has no letter J, Jesus/Yeshua was first and foremost a Jewish Rabbi, meaning he would have observed all of the Jewish holidays and customs.) For starters, the Christmas tree developed in early modern Germany, where it is today called Weihnachtsbaum or Christbaum, with predecessors that can be traced to the 16th and possibly 15th century, in which "devout Christians brought decorated trees into their homes".
You know the tradition of kissing under the mistletoe? Well, the use of mistletoe can be traced back to ancient druids who believed it held magical powers, brought good luck to households, and like jack-o-lanterns, ward off evil spirits. The notion of mistletoe creating love and celebrating with it came from Norse mythology, while kissing under the venerable plant got started in jolly old England. The original custom of kissing involving mistletoe (now often hanging over doorways and in hallways or being carried by someone who wanted to make certain of getting that kiss) began as something of a game started by such that if someone could pick a berry from the sprig of the plant and there were no more berries, the kissing would cease.
Those are just some examples. So much of what’s equated with the Christian religion is really borrowed from or “in answer to” other, most often older, religions.