Johann Martin Lappenberg (July 30, 1794 – November 28, 1865) was a German diplomat, groundbreaking medievalist, and historian with a focus on the early Holy Roman Empire, the Hanseatic League, and Saxon England.
He was born at Hamburg, where his father, Valentin Anton Lappenberg (1759–1819), held an official position.
He continued to study history in London, at Frederick William University of Berlin and at Göttingen, where he graduated as doctor of laws in 1816.
[1] For the Monumenta Germaniae historica he edited the Chronicon of Thietmar of Merseburg, the Gesta Hammenburgensis ecclesiae pontificum of Adam of Bremen and the Chronica Slavorum of Helmold, with its continuation by Arnold of Lübeck.
Lappenberg, who was a member of numerous learned societies in Europe, wrote many other historical works.