Career
He was admitted to the bar and practised law for a short time in his native city, where he became a judge of the civil court. He contributed frequently to the Revue des Questions Historiques, of which he became editor in 1904, and to various other publications. In 1874 he translated James Spencer Northcote and West. R. Brownlow"s Roma Sotterranea, making many additions and annotations to lieutenant
Paul Allard and Alexander de Richemont were all closely united to De Rossi by the interests of their common work.
The work was planned on very broad lines. The action of the Roman authorities he regarded as ill-advised and brutal.
The causes of the persecutions he finds in the blind hatred of the Roman authorities against this "third race", in fanaticism, popular fury, or, as in the case of Maximus and Decius, very largely in private spleen. have not been generally accepted.