The Coptic tradition preserves two doctrinal letters attributed, respectively, to Bishop Epiphanius of Salamis (?) and to a figure named Rufinus or Rufianus. These two texts, found in three manuscript witnesses and extant only in Coptic, are embedded within canonical and conciliar material. Each of them contains a profession of faith that articulates the respective bishop's position on key doctrinal issues central to late fourth-century theological debates. This paper explores the relationship between the letter ascribed to Epiphanius and his known works, while also seeking to shed light on the otherwise obscure figure of Rufinus/Rufianus. Both texts will be analyzed in the broader context of the "Neo-Nicene" theological agenda and the doctrinal controversies that marked the post-Nicene period.