This paper presents the earliest known fifteenth-century account of a Muslim taken captive by other Muslims. The document was sent from the Mamluk imperial capital Cairo and composed by an anonymous Ottoman officer who was captured after a disastrous Ottoman loss in February or March 1486 during the Ottoman-Mamluk war between 1485-1491. Catalogued as a petition in the Ottoman archives, the letter combines the characteristics of captivity narrative and advice literature. Captivity narratives have long been recognized for their central importance in early modern European historiography. Whereas the vast majority of texts considered by the broader field of captivity studies were produced by captives imprisoned by their religious adversaries, this document invites us to consider the intricacies of narratives produced by captives held by their Muslim co-religionists. More specifically in Ottoman studies, most available captivity narratives and research concern Christian European-Muslim Ottoman cases. The number of Muslim-to-Muslim captivity retellings are likely to increase with rising scholarly interest in sources that have been primarily overlooked so far such as letters. Produced through the lens of a once notable Ottoman officer, this text reveals how an Ottoman subject, who for a moment lived at the interstices of the two Muslim empires, chooses to present his allegiances and affiliations that he had once cultivated with the prominent individuals in the Mamluk lands. A close reading of this text reveals that his networks played an integral role in the formation of his identity and self-presentation. As illustrated by previous studies, similar networks within the Muslim world were ubiquitous and they fostered the sense of belonging to a greater community. Nonetheless, demonstrating loyalty to the Ottoman polity over religion seem essential for this captive to secure his redemption from captivity, and he achieved this task by proving his usefulness to his sovereign through advice and intelligence. Thus, this account first speaks to the complexity of entangled, yet competing, Ottoman-Mamluk encounters, and secondly, it enriches our current understanding of captivity narratives as texts illustrating the dichotomies between identities that were considered ideologically oppositional.