In the last decades of the 13th and in the first half of 14th century, Hungarian Franciscans played an important role in the Christian proselytization conversion of the Golden Horde. Some of them achieved a great career in the court of the Golden Horde’s Khans. For example, Elias of Hungary was not only a trusted friend of Özbek and also of his son, but he was entrusted with a mission to the Pope; others, like the protagonist of my paper, died as a martyr in the 14th century. The Hungarian Franciscan friar, Stephan (Stephanus de Hungaria) was executed in Sarai, the centre of the Golden Horde in April of 1334. There are a lot of references to his martyrdom in the sources of the Franciscan Order and some of them contain details of the events leading to his execution and about his death. The most important is the Chronicle of the Twenty-Four Generals of the Order of Friars Minor (Chronica viginti quattuor generalium ordinis minorum) written by Arnald of Sarrant in 1360–1370s. Although, Stephan’s passio is characterized by general characteristics of its genre, it contains a lot of useful information on the history of the Golden Horde and the history of the Christian missions on its territory. Some information of the passio can contribute to refining and clarifying other disputed data concerning the history of the region. This paper introduces the passio and analyses its historical data.