The son of the rabbi and the head teacher Samuel Dessau studied in Berlin, among others, Theodor Mommsen, who promoted him later, and received his doctorate in 1877 in Strasbourg. He led for the led by Mommsen long-term project Corpus Inscriptionum Latinarum (CIL ) of the Prussian Academy of Sciences by a research trip to Italy and North Africa and habilitated in 1884 in Berlin for Ancient History. From 1900 to 1922 he was a research officer at the CIL, in 1912 associate, from 1917 ordinary honorary professor at the University of Berlin. Due to his Jewish origins it was Dessau not possible to attain a full professorship in Wilhelmine Germany.
Dessau was buried in his native city of Frankfurt am Main.
Hermann Dessau's brother Bernardo Dessau (1863-1949) was professor of physics at the University of Perugia and founder of the first Zionist magazine in Italy ( Il Vessillo Israelitico ), while Hermann Dessau both Zionist as well as Jewish- reformist aspirations towards remained extremely cautious.
Dessau's main focus was the Latin epigraphy; for the CIL, he published several volumes. Above all, his name is associated with a still important choice collection of nearly 10,000 Latin inscriptions Inscriptiones Latinae selectae ( 1892-1916 ), the ( " D. " for short ) is sometimes also called " Dessau " quotes.
In addition, Dessau was one of the editors of the first edition of Prosopographia Imperii Romani of the Prussian Academy of Sciences. For the evaluation and exploration of the Historia Augusta his 1889 essay published over time and the Scriptores Historiae Augustae personality was fundamentally. Dessau authored more than 600 technical articles for the Realencyklopädie of classical archeology.
Dessau's three-volume, based on own research source, and therefore in many individual findings differ from the traditional scientific views history of the Roman Empire (1924-1930), which he wrote in retirement remained unfinished.
Writings (selection )
- Over time, and personality of the Scriptores historiae Augustae. In: Hermes 24 (1889 ), pp. 337-392.
- Inscriptiones Latinae selectae. 3 volumes into 5 volumes. Weidmann, Berlin 1892-1916.
- History of the Roman Empire. 2 volumes into 3 volumes. Weidmann, Berlin 1924-1930.