The origin and traditional customs associated with Halloween require no other explanation than that they are examples of the kinds of festivity that served as a means of celebrating the various holy days of the Catholic Liturgical Year. This includes everything from masquerades, feasting, and the associations of a given day of the year with supernatural or spiritual truths.
I would draw a distinction between the violent, macabre imagery that characterizes the modern appropriation of Halloween as a kind of secular celebration and the more traditional customs that are characteristic of a Catholic cultural ethos. The descent of Halloween into the madness of an annual fright fest is a relatively recent development, but the true substance of Halloween belongs to the Church. Halloween (or “All Hallows Eve”) is the festive precursor to the celebration of the Church’s public commemoration of All Saints Day.
There has been an appropriation of the festivities of Halloween by modern pagans, but please understand that modern paganism is precisely modern and should be distinguished from the cults of ancient religions. The origins and practices of the modern paganism do not extend farther back than the late nineteenth century. Also, remember, the term “pagan” is a slippery one. What does it mean? The worship of the gods and goddesses from long ago? Those cults have long since passed away with the cultural matrix that once supported the world views that were the conditions for their possibility. You can’t just reinvent those cults without the culture that supported them.
I think that the association of Halloween with paganism has much more to do with the Protestant Reformation than anything else. The Protestant reformers were concerned about the practices of medieval Christianity that to them seemed contrary to what they believed the Church should be. They knew that these practices had clear precedents in the history of the Church, but insisted that they represented a corruption of the original form of Christianity that had become degraded over time. The degradation was explained as a regression into cultural forms that the Protestants described as pagan.
I realize popular religiosity is a complex phenomenon and the Church in Europe did intentionally assimilate many cultural practices that were more ancient than its own practices, but it did so selectively and with a keen sense of discernment. The end result was not simply that a veneer of Christianity was placed on top of an ancient pagan ethos, but that a new cultural matrix was created, one that was Christian to its core. It is a gross mischaracterization and oversimplification to assert that you can just scratch the surface of medieval Christianity and what rises up is paganism.
And yet this perception endures in contemporary culture. You see it, for example, in works of fiction like Marion Zimmer Bradley’s The Mists of Avalon, which appropriates ideas from a lot of spurious, pseudo scholarship that permeated British intellectual culture throughout the nineteenth and early twentieth century. Unfortunately, this has become a standard and widely accepted narrative of how Europe became Christian. It is a modern myth born of the prejudices and propaganda of the Protestant reformation that mutated into the secular critique of Catholicism. As an ideological construct it represents the simultaneous fascination and aversion to Medieval culture in general and Catholicism in particular. The reality is far more complex and interesting.
Protestantism was and is proposing what its adherents believe to be an alternative to Catholicism. This means that Protestantism will distinguish itself from the forms and styles of religious life that preceded their own culture and that this culture will be presented as a purified form of Christian faith and practice. One argument that is advanced to justify Protestant distinctiveness is that the beliefs and practices of the Catholic Church are pagan.
As a result, the distinctly Catholic nature of Halloween became more and more muted and it was Catholics pulling back from their own festival that gave rise to the contemporary version of Halloween. The ghoulish version of the festival that we have today is in many respects a result of Catholic accommodation to a Protestant culture. And in another strange twist in the history of Halloween, most everything that the devout Protestant detests about Halloween have become all the more pronounced as a result of their protests.