Monumenta Germaniae Historica – The Monumenta Germaniae Historica (MGH) is a comprehensive series of carefully edited and published primary sources, both chronicle and archival, for the study of Northwestern and Central European history from the end of the Roman Empire to 1500.[1] Despite the name, the series covers important sources for the history of many countries besides Germany, since the Society for the Publication of Sources on Germanic Affairs of the Middle Ages has included documents from many other areas subjected to the influence of Germanic tribes or rulers (Britain, Czech lands, Poland, Austria, France, Low Countries, Italy, Spain, etc.). The editor from 1826 until 1874 was Georg Heinrich Pertz (1795–1876); in 1875 he was succeeded by Georg Waitz (1813–1886).

Monumenta Germaniae Historica – Wikipedia

https://en.wikipedia.org/wiki/Monumenta_Germaniae_Historica

The Monumenta Germaniae Historica (MGH) is a comprehensive series of carefully edited and published primary sources, both chronicle and archival, for the study of Northwestern and Central European history from the end of the Roman Empire to 1500.[1] Despite the name, the series covers important sources for the history of many countries besides Germany, since the Society for the Publication of Sources on Germanic Affairs of the Middle Ages has included documents from many other areas subjected to the influence of Germanic tribes or rulers (Britain, Czech lands, Poland, Austria, France, Low Countries, Italy, Spain, etc.). The editor from 1826 until 1874 was Georg Heinrich Pertz (1795–1876); in 1875 he was succeeded by Georg Waitz (1813–1886).