The Martyrologium Hieronymianum (meaning "martyrology of Jerome") is a list of Christian martyrs, one of the most used and influential of the Middle Ages. It is the oldest surviving general or "universal" martyrology, and the ultimate source of all later Western martyrologies. It was probably compiled in the late 6th century by monks in Gaul from calendars or martyrologies originating in Rome, Africa, the Christian east, as well as those which arose locally.
Pseudepigraphically attributed to Saint Jerome, the Martyrologium Hieronymianum contains a reference to him derived from the opening chapter of his Vita Malchi (392 AD) where Jerome states his intention to write a history of the saints and martyrs from the apostolic times: "I decided to write [a history, mentioned earlier] from the coming of the savior up to our age, that is, from the apostles, up to the dregs of our time". Its alternate name, Martyrologium sancti Hieronomi, further erodes confidence about its authorship.
Hippolyte Delehaye was of the opinion that the first recension was compiled in northern Italy, probably within the patriarchate of Aquileia, in the 430s or 440s. The 1911 Encyclopædia Britannica suggested that in its present form it goes back to the end of the 6th century: "It is the result of the combination of a general martyrology of the Eastern Churches, a local martyrology of the Church of Rome, some general martyrologies of Italy and Africa, and a series of local martyrologies of Gaul. The task of critics is to distinguish between its various constituent elements." The sole surviving manuscript derives from a lost recension apparently made in Gaul, probably at Auxerre, ca 600, with which the Dictionary of the Middle Ages concurs. The text shows signs of having been copied in Anglo-Saxon England by its inclusion of five Anglo-Saxon commemorations. The sole surviving copy (Epternacensis) is associated with the household of the Northumbrian Willibrord, at his foundation, Echternach; it is conserved at the Bibliothèque nationale, Paris, lat. 10837, folios 2 - 33.