The early Church was neither Roman Catholic nor Protestant in the modern senses of those terms, but rather an organic, apostolic fellowship centered on the gospel that preceded the formal ecclesiastical divisions we see today. Reformed theologians view the early Church as a true, albeit developing, body that held to the core creeds while undergoing a historical progression in its administrative and liturgical structures.
The Reformed tradition, as expressed in the , teaches that there is only one catholic Church throughout all time, bound together by one Lord, one faith, and one Savior. The Church is not defined by allegiance to a specific earthly see, but by the faithful reception and proclamation of the gospel, which Paul describes in as the fundamental message that Christ died for our sins, was buried, and was raised on the third day. Because this gospel has been the lifeblood of the people of God from the patriarchs through the apostles, the Church exists in a state of unity that transcends the later institutional boundaries of East and West. The early believers, as seen in , devoted themselves to the apostles' teaching and fellowship, looking to Christ as the only Head of the body. This primitive unity was grounded in the truth of the Word rather than in the administrative hierarchy that would later characterize the Roman See.
While Roman Catholic apologetics often argue that the early Church was inherently Roman, Reformed theologians like John Calvin argue that this claim misinterprets historical records. In the , Calvin explains that the early Church held the Roman Church in high honor for specific historical reasons—such as its location in the seat of empire and its relative stability during times of doctrinal turmoil—but this did not imply a divine mandate for Roman supremacy. Similarly, the Lutheran notes that ancient synods, such as the Council of Nicaea, were held without the presidency of a Roman bishop, and that bishops across the world were considered equal in dignity and priesthood. The early Church functioned through the common consultation of elders, and the eventual rise of a singular head over the others is understood by Reformed writers to be a result of human custom and historical necessity rather than an essential component of the Church's divine constitution.
The Reformed and Lutheran traditions share a critical perspective on the Roman claim to the early Church. The (Article VII) defines the Church as the 'congregation of saints' where the gospel is rightly taught and the sacraments are administered, emphasizing that unity is found in doctrine, not in the uniformity of human traditions or papal oversight. This aligns with the (Chapter 25, Section 4), which asserts that the visibility and purity of the catholic Church fluctuate based on how purely the gospel is taught. In contrast, the Roman Catholic position—as summarized in its own historical apologetics—affirms that the current Roman institution is the direct and necessary continuation of the apostolic foundation laid on Peter. The Reformed sub-traditions (Presbyterian, Baptist, and Continental Reformed) generally agree that the early Church was not 'Roman Catholic' in the post-Trent sense, but they may differ in their specific critiques of later developments in church government and liturgy. However, they all agree that the 'Catholic' (universal) Church is defined by faithfulness to Scripture rather than organizational succession alone.
It is crucial to approach this history with a gospel-centered lens. The early Church was a communion of sinners saved by grace, and while they wrestled with errors and administrative developments, their identity remained in the completed work of Christ. Calvin warns in the (Chapter 2) that the 'pretence of succession is vain' if posterity does not retain the truth of Christ as it was handed down by the fathers. This means the mark of a true church is the preservation of the gospel of justification by faith alone, not merely the historical continuity of bishops. For the modern Christian, the lesson of the early Church is that we are united to the same saints, by the same Spirit, through the same Word. As the reminds us, this catholic faith is that which must be held faithfully, as it centers entirely on the mystery of God's grace in Christ. Even if one finds that the early Church was 'Catholic' in its nascent organizational structure, one must distinguish this from the later developed system that the Reformers identified as a perversion of the gospel. The early Church was a church in progress, always standing under the judgment and authority of the Scriptures.