But he was also deeply rooted in the classical spirit of the Age of Enlightenment in his intellectual presuppositions, his use of philologic analysis, and his emphasis on both general and particular phenomena in history.
[4] In 1796 he left Kiel to become private secretary to the Danish finance minister, Count Schimmelmann, but in 1798 he gave up this appointment and travelled in Great Britain, spending a year at Edinburgh studying agriculture and physics.
He accompanied the fugitive government to Königsberg, where he rendered considerable service in the commissariat, and was afterwards still more useful as commissioner of the national debt and by his opposition to ill-considered schemes of taxation.
The extreme sensitiveness of his temperament, however, disqualified him for politics; he proved impracticable in his relations with Hardenberg and other ministers, and in 1810 retired for a time from public life, accepting the more congenial appointment of royal historiographer and professor at the university of Berlin.
In 1813 Niebuhr's own attention was diverted from history by the uprising of the German people against Napoleon; he entered the Landwehr and ineffectually sought admission into the regular army.
He edited for a short time a patriotic journal, the Prussian Correspondent, joined the headquarters of the allied sovereigns, and witnessed the battle of Bautzen, and was subsequently employed in some minor negotiations.
[4] On his way to Rome, he discovered in the cathedral library of Verona the long-lost Institutes of Gaius, afterwards edited by Savigny, to whom he communicated the discovery under the impression that he had found a portion of Ulpian.
The reason that Niebuhr visited Verona is a matter of controversy among scholars, with some alleging that he was on a "secret mission" to obtain the Gaius manuscript which others had previously found.
He also assisted in August Bekker's edition of the Byzantine historians (the Corpus Scriptorum Historiae Byzantinae), and delivered courses of lectures on ancient history, ethnography, geography, and on the French Revolution.
Leonhard Schmitz, in his 1861 preface to the English version of Mommsen's History, wrote:"The main results arrived at by the inquiries of Niebuhr, such as his views of the ancient population of Rome, the origin of the plebs, the relation between the patricians and plebeians, the real nature of the ager publicus, and many other points of interest, have been acknowledged by all his successors.
By his theory of the disputes between the patricians and plebeians arising from original differences of race he drew attention to the immense importance of ethnological distinctions, and contributed to the revival of these divergences as factors in modern history.
"[5] More modern perspectives on Niebuhr's work maintain that, although some of his hypotheses were extravagant, and his conclusions mistaken, he introduced a constructive, scientific approach to the critical and sceptical consideration of ancient literary sources, especially with regard to their poetic and mythical embellishments.