"But whereas the pagans observed the solstice in terror, feverishly keeping the fires going lest the darkness overcome them, Christians turned what was literally the dead of winter into the happiest time of the year. The time of year now meant that when darkness is at its greatest, the light of God — Jesus Christ — is born. Gradually, though the night is still longer than the day throughout the winter, the light increases every day. Finally, the light surpasses the darkness. This occurs just after the spring equinox, March 21, another favorite time for holidays in the world's religions. Around that time Christians celebrate Easter, the day Christ rose from the dead, marking His victory over sin, death, the devil, and every darkness.
seasonal symbolism of light and darkness, Christmas and Easter go together.
Christmas marks the beginning of the light, and Easter marks the triumph of
the light, just as the birth of the Christ child marks the beginning of His
work, which culminates in the victory of His death and resurrection."
(You can read Veith's entire article at http://www.worldmag.com/world/issue/12-21-02/cultural_1.asp)