Since the times of early Mesopotamia celebrations, there were grand celebrations with bonfires, yule log, sharing of gifts, carnivals and parades during the time that is now known as Christmas season in the honor of their chief god, Marduk. It was believed that every year the God had to wage a war with monsters of chaos in the winter season and the Mesopotamian king had to swear his faithfulness to the god and return with Marduk to battle at his side. This called for sacrifice of the king, which was indeed not a practical thing to do and hence a criminal condemned to death was crowned as the 'mock king' and dressed in royal dress and given all the privileges and respect of the king and then was sacrificed like the King himself. Ancient Greeks had a similar festival where their God Kronos fought against the tyrant God Zeus and his Titans.
Persians and Babylonians celebrated the festival of Sacaea to spread the message of universal love. 25th December has been sacred to the pagans of Romans and the Persians following Mithraism as their religion and on this day, the slaves swapped positions with their masters and could treat the masters as their slaves. Early superstitious Europeans performed special rituals during the Winter Solstice to persuade the sun to come back as they believed that winter was the season for evil spirits, witches, ghosts and trolls. Scandinavians even sent scouts to look for sun on the mountaintops who would rush back to the village as soon as they saw the first rays of the sun to deliver the good news. The good news was enough cause for them to celebrate Yuletide, when a great feast was held around the bonfires made of Yule logs. Some of the people would tie apples on the branches of the coniferous trees in the hope of approaching Spring and Summer.
Romans celebrated Saturnalia from mid-December to 1st of January in the honor of their pagan god Saturn that featured shouts of 'Jo Saturnalia!' masquerades, grand feasts and exchange of Strenae or lucky fruits as gifts. Christmas, in its early days, was observed as the solemn and religious holiday as the birth of Christ that merged later on with the joyous activity of Saturnalia with the increasing number of converts until at last church approved of these celebrations within certain limits. It is believed that Christmas celebrations are being held since 98 AD though; it was 39 years later that the Bishop of Rome ordered a solemn feast to be held every year to the Christmas Eve. It took more than another two centuries for the Bishop of Rome, Julius I, to chose December 25th as the day of observance of Christmas.