When the German Frankish king Charlemagne invaded and conquered parts of Eastern Germany, he compelled the conquered German king, Wittekind, to be baptized and to accept Christianity. Having no choice and seeing his life was at stake, this heathen ruler who knew little or nothing about Christ -- was forced into this "conversion." And with him his entire people. This policy brought complex problems. These pagans, who were usually baptized EN MASSE, were still pagans at heart. Even though they became nominal Christians, they still yearned for many of their heathen practices, which they were expected to discard.
With Wittekind's baptism, for example, a vast number of barbarians were suddenly added to the roll call of the church. Wittekind's Germans, now professing Christians, and other conquered pagans, had a profound influence on the ecclesiastical affairs of the church in the early 800's A. D. These barbaric and uncultured people brought with them many outright pagan practices and celebrations, Hallowe'en merely being one of many. They were fervent in clinging to their past ceremonies and observed them openly -- yet supposedly converted to Christianity. What was the church to do? Excommunicate them and thus reduce her membership? This she would not do. Was she to force them into discarding their heathen practices and adopt Italian or Roman ones? This, as she had learned in past times, was not possible.
There remained only one other way. Let the recently converted pagans keep certain of their heathen festivals, such as Hallowe'en or All Souls Day -- but label it "Christian." Of course the Germans were asked not to pray to their ancient pagan gods on this day. They must now use this day to commemorate the death of the saints. To make it easy for them, the Roman Church even CHANGED HER DATE of All Saints Day from May 13 to November 1st to satisfy the growing numbers of Germanic adherents. The Church understood the yearnings the Germans and others had for their old ways.
Throughout history, the Christian-professing world has resorted to this action. We have the theological explanation of this given to us by Pope Innocent. He refers to a heathen festival the pagans kept in the early part of the Roman Empire and explained how the professing Christian world should treat this day:
"The heathen dedicated this month [2 Feb.] to the infernal gods ... In the beginning of this month the idolaters walked about the city with lighted candles, and as some of the holy fathers COULD NOT EXTIRPATE SUCH A CUSTOM, they ORDAINED that Christians should carry about candles IN HONOUR OF THE "VIRGIN MARY" ("Folklore", James Napier, p. 181).
If a pagan practice or festival could not be forbidden, it was reasoned, "let it be tamed." Thus many were persuaded to TRANSFER devotion from their former gods to the Christian God. So it was with the festival of ALL SOULS EVE. Notice this admission: "Thus, at the first promulgation of Christianity to the Gentile nations ... THEY COULD NOT BE PERSUADED TO RELINQUISH many of their superstitions, which, rather than forego altogether, they chose to blend and INCORPORATE with the new faith" ("Popular Antiquities of Great Britain", John Brand, p. xi).