The Roman Saturnalia
Scholars are generally in agreement that Christ was born in latter March or early April.
The ancient Romans celebrated the SATURNALIA from the 19th to the 25th of December in honor of Saturn, an ancient King of Sicily, who brought prosperity to the land. The Winter Solstice, 21st/22nd of December is the central part of the SATURNALIA because the shortened days now grow longer with the sun returning to the earth. The Romans celebrated this 7 day festival by exchanging gifts, decorating pine trees, permitting slaves to dine with their masters and exhibiting extraordinary kindness to one another. As centuries passed the SATURNALIA lost its religious tone and degenerated into a Bacchanalian holiday.
As Christianity grew the leaders of the church decided to reduce the pagan influence of the SATURNALIA with a feast of their own. They thought it fitting to celebrate the birth of Christ at this time to give the Christians a reason to celebrate the return of the Sun/Son (of God) to earth.
And so, Christmas gradually replaced the SATURNALIA.