The work concerns the development of the legend about the Sandomierz martyrs from the period 1259/1260. It was then that a large part of the city's inhabitants were massacred, including the Dominicans from the monastery of St. Jacob. Public opinion was deeply shocked, which resulted in the spontaneous development of the cult of martyrs. This was especially strengthened during the period of propagation of indulgence, which provided remission of temporal punishments for 366 years to the faithful who visited the Sandomierz collegiate church on the day of the holy martyrs. At the end of the Middle Ages, a special cult of Dominican martyrs began to emerge, which later flourished, especially during the Counter-Reformation. In the 16th century, it was accidentally associated with the Hungarian cult of Zadok, the abbot of the Zagreb Dominicans and his 48 brothers. At the end of the 17th century, Zadok's biography was enriched with Hungarian motifs. From then on, in literature we either distinguished two martyrs with the same name or identified them. The basis for confirming the Dominican cult was its duration and testimonies of graces received through the intercession of matryras, widely collected in the 17th and 18th centuries. In the 19th century, the cult of the Sandomierz martyrs deteriorated, while Zadok and his companions were beatified in 1807, thanks to the efforts of Polish Dominicans. . However, currently the cult of the Sandomierz martyrs (including the Dominicans) is no longer particularly popular.