William Sandys, Christmastide: Its History, Festivities…
“ These Christmas boxes, like New Year’s gifts, are probably of pagan origin, but seem to differ, inasmuch as they are more commonly given to dependents, while the latter are frequently reciprocal, and if given by an inferior, as an offering to a superior, meet generally with some return. Some have derived the Christmas box from the practice of the monks to offer masses for the safety of all vessels that went long voyages, in each of which a box, under the controul of the priest, was kept for offerings ”
