Early church historians generally agree on what constituted the earliest rudimentary form of the creed known as the regula fidei. However, the relationship between this proto-creed and the versions of the baptismal confession, occasionally produces some scholarly debates. For example, while some scholars like Adolf von Harnack, argue that the regula fidei was kind of like a hard copy of the primitive baptismal confession, others like Bart D. Ehrman reject it altogether, arguing instead for an expanded view of early Christianity that includes such groups as the Marcionites and the Gnostics. This paper advances this discussion by arguing that the regula fidei, was neither the same as the baptismal confession nor was it so expansive to include these groups. Rather, it provided a guardrail for orthodoxy while allowing legitimate theological diversity in the early church. This thesis will be defended through a contextual examination of the wording of the regula fidei in the works of such fathers as Clement of Rome (e.g., 1.00 Clem. 46.6), Ignatius of Antioch (e.g., Mag. 8.2; Eph. 15.3; 18.2, Rom. 3.3; Pol. 8.3), Irenaeus of Lyons (e.g., Adv. Haer. 1.3.6; 1.10.1; Epid. 6), and Tertullian (Praescr. 13).