In England, the Christmas cake began as a Twelfth Night cake, Twelfth Night being on 5th January and marking the end of the Christmas season. Twelfth Night was a great celebration and often the local priest would visit and bless the houses, and would be invited to take a piece of this cake.
After the Reformation this religious tradition died out, but enterprising bakers, no doubt seeing a gap in the market and missing their lost revenue , revived the cake, decorating it with Christmas scenes. So, Twelfth Night cake became Christmas cake!
Traditional Christmas cakes were made in advance, usually no later than November. The cake would be kept upside down in an airtight tin. Every week a small amount of brandy, sherry or whisky would be 'fed' into holes in the cake, until Christmas.