Bernardino de Ávila Girón was a Spanish merchant and notary who lived in Japan between 1594 and 1619. He traveled from Spain to Manila around 1583, took up residence in Nagasaki and was living there when six missionaries and twenty Japanese were crucified on February 5, 1597. He witnessed the persecution of Christians after the edict of expulsion of European missionaries on February 14, 1614. Based on these experiences and his observation of Japanese customs, he wrote the Relación del reyno del Nippon al que llaman corruptamente Jappon, the only secular account written in Spanish about Japan and the failed expansion of Christendom in the sixteenth and seventeenth centuries. The ties linking seventeenth-century Spain and the Americas in literature have been widely explored. Literary critics have studied the relationship between Spain and Asia in the context of medieval travel writing and nineteenth- and twentieth-century Orientalism. The relations between the Spanish empire and the empires of Asia, however, have been studied mostly by historians. My dissertation examines Bernardino de Ávila’s work not as a historical account, but as a narrative composed by a layman who would not have been considered in the seventeenth century either a historian or a reliable chronicler of martyrdoms. However, he provides a valuable and memorable eyewitness account that defies categorization. I use published sources and archival documentation to establish a more complete biography of Bernardino de Ávila, study the textual transmission of the Relación, a work that exists in multiple copies, place the Relación and Bernardino de Ávila’s life in historical context, and focus on its relation to other historical and literary writing of the period, including writing on the Japanese martyrs by the Jesuit Pedro Morejón and the playwright Lope de Vega, who were writing for very different readerships. I define the genre of the Relación and examine ideas of authority in the writing of history and hagiography and conclude by tracing the history of this work from the seventeenth century to our own day, and offer an explanation of why it has been excluded from the literary and historical canon.