Though candles placed in a home's windows is little more than a Christmas tradition now, the practice was originally meant to welcome and guide people to the home. In Colonial America, candles in the window were also a way to announce good new.
The practice of placing candles in the window has its roots in Irish culture. During the period of religious suppression by the English, no public churches were allowed. Priests who had formerly performed Sunday and holiday services hid in forest and fields surrounding villages, and they would visit individual homes at night to say mass. During the holidays, people would light candles in their windows and leave their doors unlocked in the hope that a nearby priest would visit and say the holiday services in their home.