The Martyrologium Hieronymianum or Martyrologium sancti Hieronymi (both meaning "martyrology of Jerome") is an ancient martyrology or list of Christian martyrs in calendar order, one of the most used and influential of the Middle Ages. It is the oldest surviving general or "universal" martyrology, and the precursor of all later Western martyrologies.
Pseudepigraphically attributed to Saint Jerome, the Martyrologium Hieronymianum contains a reference to him derived from the opening chapter of his Lofe of Malchus (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".
The Martyrologium Hieronymianum appears to have drawn for its material on the existing calendar of Rome, on one from Africa, and on a compilation made in Greek around the year 362 A.D. and which used as a major source the details found regarding the martyrs in works of Eusebius of Caesarea. The contents of the 362 AD compilation are known to us from an untidy Syriac translation which survives in a copy dateable to 411 AD. It is the geographical spread of the sources which gave this pioneering martyrology its general or "universal" character. Nevertheless, on account precisely of this non-local character and because the date of final compilation considerable postdates the end of the main anti-Christian persecutions, the antiquity of much of the information gathered is undermined by the inevitable errors caused by multiple compilers and by scribes to whom the persons mentioned could not have been personally unknown. It appears that the initial Latin text was fabricated in Northern Italy, probably within the Patriarchate of Aquileia, in the 430s or 440s. but then later reworked in Gaul, probably at Auxerre, about the year 600. It is from this line of transmission that the surviving manuscripts descend.
The three earliest manuscripts which do survive of the Latin Martyrologium Hieronymianum as such are all relatively late, from the 8th century, which means they have inevitably suffered interference in the course of transmission. The oldest of them comes from the monastery of the Northumbrian missionary St Willibrord at Echternach and was written in England in the first years of the 8th century. Two other important manuscripts were written in the same century, one for the monastery of Saint Avoldus near Metz, and the other was copied by 772 AD for the monastery of Saint-Wandrille and then came to the monastery of St Peter in Wissembourg.