This study aims to provide a general-examined understanding of a specific “source text," or “sources excerpt," explaining the context and content of that text and its sources. It also provides a piece of brief information about the writer or historian, his method, his works, and his life, analyzing the text and its contextualization in connection with other works or events. This article endeavors to study and analyze the letter of 656/1258 addressed from Hulagu Khan (r. 654/1256- 663/1265) to al-Malik al-Nāṣir of Aleppo (r. 633-34/ 1235- 658/1260).  The Syrian cleric and scholar Ibn al-ʿIbrī (d.c.685/1286) was present at Aleppo during this time and had the precedence, among his Arab, Latin, Syrian and Persian contemporaries, to record such a letter in his unique Arabic chronicle Tārīḫ Muḫtaṣar al-duwal.  Therefore, this article studies the discourse of the writings and life of Ibn al-ʿIbrī, provides an examination for the context and content of the said letter and in which historical context it was written.  I propose to determine the Latin perception of Prester John in the figure of a Mongol ruler, especially Genghis Khan during the Fifth Crusade, and the late imagined perception in Hulagu Khan. Eventually, I analyze, contextualize, and interpret the letter and its historical context, comparing it with some (selective) contemporaneous and subsequent sources.