Hagiographer Anonymous I is the name given by modern scholars to an unknown Christian author who lived during the 3rd or 4th century CE, a period known as Late Antiquity. No biographical details about this individual survive. The name is a scholarly convention used to identify the writer of a specific early Christian text.

This author wrote within the tradition of early Christian hagiography, which are narratives celebrating saints and martyrs. Their sole surviving work is The Martyrdom of Saints Carpus, Papylus, and Agathonice, a Greek prose account of the deaths of these early Christian figures. According to modern scholars, texts like this were often written by clerics or devout community members to inspire believers, promote the veneration of local saints, and reinforce ideals of faith.

The historical importance of this anonymous writer lies in their contribution to the formative literature of early Christianity. Their martyrdom account provides a window into the religious ideals and social challenges faced by Christians in the Roman Empire. It is considered a valuable source for understanding how stories of martyrdom helped shape early Christian identity, collective memory, and liturgical practices.