The evergreen fir tree has traditionally been used to celebrate winter festivals (pagan and Christian) for thousands of years. Pagans used branches of it to decorate their homes during the winter solstice, as it made them think of the spring to come. The Romans used Fir Trees to decorate their temples at the festival of Saturnalia. Christians use it as a sign of everlasting life with God.
Nobody is really sure when Fir trees were first used as Christmas trees. It probably began about 1000 years ago in Northern Europe. Many early Christmas Trees seem to have been hung upside down from the ceiling using chains (hung from chandeliers/lighting hooks).
Other early Christmas Trees, across many parts of northern Europe, were cherry or hawthorn plants (or a branch of the plant) that were put into pots and brought inside so they would hopefully flower at Christmas time. If you couldn't afford a real plant, people made pyramids of woods and they were decorated to look like a tree with paper, apples and candles. Sometimes they were carried around from house to house, rather than being displayed in a home.
It's possible that the wooden pyramid trees were meant to be like Paradise Trees. These were used in medieval German Mystery or Miracle Plays that were acted out in front of Churches on Christmas Eve. In early church calendars of saints, 24th December was Adam and Eve's day. The Paradise Tree represented the Garden of Eden. It was often paraded around the town before the play started, as a way of advertising the play. The plays told Bible stories to people who could not read.
The first documented use of a tree at Christmas and New Year celebrations is argued between the cities of Tallinn in Estonia and Riga in Latvia! Both claim that they had the first trees; Tallinn in 1441 and Riga in 1510. Both trees were put up by the 'Brotherhood of Blackheads' which was an association of local unmarried merchants, ship owners, and foreigners in Livonia (what is now Estonia and Latvia).
Little is known about either tree apart from that they were put in the town square, were danced around by the Brotherhood of Blackheads and were then set on fire. This is like the custom of the Yule Log. The word used for the 'tree' could also mean a mast or pole, tree might have been like a 'Paradise Tree' or a tree-shaped wooden candelabra rather than a 'real' tree.
In the town square of Riga, the capital of Latvia, there is a plaque which is engraved with "The First New Year's Tree in Riga in 1510", in eight languages.
A picture from Germany in 1521 which shows a tree being paraded through the streets with a man riding a horse behind it. The man is dressed a bishop, possibly representing St. Nicholas.
In 1584, the historian Balthasar Russow wrote about a tradition, in Riga, of a decorated fir tree in the market square where the young men “went with a flock of maidens and women, first sang and danced there and then set the tree aflame”. There's a record of a small tree in Breman, Germany from 1570. It is described as a tree decorated with "apples, nuts, dates, pretzels and paper flowers". It was displayed in a 'guild-house' (the meeting place for a society of business men in the city).
The first person to bring a Christmas Tree into a house, in the way we know it today, may have been the 16th century German preacher Martin Luther. A story is told that, one night before Christmas, he was walking through the forest and looked up to see the stars shining through the tree branches. It was so beautiful, that he went home and told his children that it reminded him of Jesus, who left the stars of heaven to come to earth at Christmas. Some people say this is the same tree as the 'Riga' tree, but it isn't! The Riga tree originally took place a few decades earlier. Northern Germany and Latvia are neighbors.
Another story says that St. Boniface of Crediton (a village in Devon, UK) left England and traveled to Germany to preach to the pagan German tribes and convert them to Christianity. He is said to have come across a group of pagans about to sacrifice a young boy while worshiping an oak tree. In anger, and to stop the sacrifice, St. Boniface is said to have cut down the oak tree and, to his amazement, a young fir tree sprang up from the roots of the oak tree. St. Boniface took this as a sign of the Christian faith and his followers decorated the tree with candles so that St. Boniface could preach to the pagans at night.
There is another legend, from Germany, about how the Christmas Tree came into being, it goes:
Once on a cold Christmas Eve night, a forester and his family were in their cottage gathered round the fire to keep warm. Suddenly there was a knock on the door. When the forester opened the door, he found a poor little boy standing on the door step, lost and alone. The forester welcomed him into his house and the family fed and washed him and put him to bed in the youngest sons own bed (he had to share with his brother that night!). The next morning, Christmas Morning, the family were woken up by a choir of angels, and the poor little boy had turned into Jesus, the Christ Child. The Christ Child went into the front garden of the cottage and broke a branch off a Fir tree and gave it to the family as a present to say thank you for looking after him. So ever since them, people have remembered that night by bringing a Christmas Tree into their homes!
In Germany, the first Christmas Trees were decorated with edible things, such as gingerbread and gold covered apples. Then glass makers made special small ornaments similar to some of the decorations used today. In 1605 an unknown German wrote: "At Christmas they set up fir trees in the parlours of Strasbourg and hang thereon roses cut out of many-colored paper, apples, wafers, gold foil, sweets, etc."
At first, a figure of the Baby Jesus was put on the top of the tree. Over time it changed to an angel/fairy that told the shepherds about Jesus, or a star like the Wise Men saw.