Final answer:
The Catholic Church adopted and aligned pagan holidays with Christian celebrations to ease conversions and merge cultural practices with Christian beliefs, achieving mass influence and societal integration.
Step-by-step explanation:
The Catholic Church adopted pagan holidays strategically to facilitate the conversion of non-Christians by aligning Christian celebrations with existing non-Christian festivals. This process involved repurposing pagan temples and holidays for Christian worship, thereby easing the transition for new converts to Christianity. Christmas, celebrated on December 25, coincided with the festival of the sun god Sol Invictus, while Easter overlapped with spring fertility festivals. Saint's days were also synchronized with non-Christian celebrations.
Such strategic alignment served dual purposes: it enabled the Church to maintain and grow its influence by attracting large crowds who funded church constructions, and it blended religious practices to harmonize with the ebb and flow of agrarian lifestyles. Fundamentally, the Church aimed to provide a framework for understanding the world, replacing pagan and animistic views with Christian doctrine and refining cultural practices to reflect Christian beliefs.
The outcome of such practices was a widespread establishment of Christianity across Europe, influencing both the calendar system and daily village life. The transition from the Julian to the Gregorian Calendar under Pope Gregory XIII is another example of how the Church reformed existing structures for long-term ecclesiastical and practical benefits.