Short answer: YES — and here’s why.

1. The Formation of the Church Before Institutional Heresy Mechanisms

The first heresies formally recognized by the Church only emerge around the eighth century, when a juridical framework finally exists to define orthodoxy and condemn doctrinal deviations. Prior to that, although intense debates, divergent theological schools, and internal tensions were present, there was no institutional structure capable of officially declaring a doctrine heretical. The Church was still in a formative phase, consolidating its identity, calendar, liturgy, and historical narrative. This context is essential to understanding how early Christianity positioned itself between Jewish heritage and the pagan environment of the Roman Empire.

2. The Effort Toward Liturgical Purification and Unification Between the 2nd and 4th Centuries

Between the 2nd and 4th centuries, the Church undertook a deliberate effort to purify and unify religious practices. This process is historically verifiable and reflects an attempt to absorb Jewish traditions, reject pagan practices, and replace non-Christian festivals with celebrations aligned with the biblical narrative. The Church sought to create a universal calendar that reflected continuity with the Old Testament while clearly distinguishing itself from the dominant paganism of the Roman world. Revising dates was not a secondary detail but a central part of constructing Christian identity.

3. The Early Catholic Church as Structural Continuation of Judaism

Theologically and institutionally, the early Church understood itself as a direct continuation of Judaism. It inherited the concept of covenant, priesthood, the centrality of Scripture, prophetic interpretation of history, and the expectation of messianic fulfillment. The Jewish lunar calendar served as a reference for early Christian celebrations, and typological readings of the Old Testament shaped interpretations of Jesus’s life. The Church saw itself as spiritual Israel—a community that extended and universalized the promise made to the patriarchs. This is not a modern interpretation but the explicit doctrine of the Church Fathers, early councils, and foundational liturgy.

4. The New Testament as Fulfillment of the Promise and Beginning of the New Priesthood

Early Christian theology did not view the New Testament as a replacement of the Old, but as its fulfillment. Pauline, Johannine, and patristic theology emphasized continuity between the promise made to Israel and its realization in Christ. The liturgy of the early centuries reflected this continuity: the Christian priesthood was seen as the unfolding and completion of the Levitical priesthood, not a rupture. Early Christianity did not perceive itself as a religion distinct from Judaism, but as fulfilled Judaism, expanded and open to all nations. This self-awareness explains why early Christian communities sought to anchor their dates and celebrations in the Old Testament.

5. Date Revision as Part of Christian Identity Construction

Before formal heresies emerged, the Church was already engaged in revising liturgical dates. Between the 2nd and 4th centuries, it sought to replace pagan festivals with Christian celebrations, align feasts with biblical events, create a calendar coherent with the Old Testament, legitimize itself as Israel’s heir, and distance itself from paganism without breaking from the Empire. This process included Easter, Pentecost, Epiphany, and later, Christmas. Revising dates was part of building Christian identity and reflected the need to unify dispersed communities under a shared liturgical cycle.

6. The Catholic Church’s Relationship with Judaism: Protection, Continuity, and Mission

For many centuries, the official position of the Catholic Church was not to persecute Jews but to protect them. Popes viewed Jews as the people of the promise and insisted they should be preserved, not destroyed. The Church’s mission was not to eliminate them but to draw them into the Christian faith through witness, not violence. Numerous papal bulls prohibited attacks on Jews, protected synagogues, and condemned forced conversions. During periods of popular or state violence, such as the Spanish Inquisition, the papacy even threatened to excommunicate monarchs who violated these directives. This posture reinforces the idea that the Church saw itself as a continuation of Judaism, not its negation.

7. Conclusion: Calendar Purification and Judeo-Christian Identity Before Heresies

Before formal heresies, the Church was actively engaged in purifying the calendar and aligning it with the Old Testament. This effort was part of its Judeo-Christian identity and its need to distinguish itself from paganism. However, when imperial power entered the process—especially under Constantine—this movement was partially redirected toward political objectives. The Christian calendar that solidified from the 4th century onward is thus the product of a complex synthesis between Jewish tradition, early Christian theology, and imperial political decisions.