What is known today as Christmas, the celebration of the birth of the Christ child, has roots from centuries before his birth. Christmas was not actually introduced into the Christain world until the fourth century. Mid winter was chosen for this celebration, largely due to the numerous pagan celebrations occurring at the same time. I'm sure The Church was focusing on converting what they viewed as heathens into the Catholic Church. It took another 200 years for the tradition of Christmas to spread to Britain, and another 200 on top of that for it to sweep across Scandanavia.
As I understand it, the Christmas celebration of those times was more akin to Mardi Gras of today. I'm pretty sure that women did not have to flash their boobs for beads back then. But you never know!