HALLER, JOHANNES. - Protestant historian, b. 16 Oct 1865 at Keinis (Estonia), d. 17 Jan 1948 at Tübingen. After completing his university studies at Dorpat, Berlin, and Heidelberg, he was in Rome from 1892 to 1897 at the Prussian Historical Institute. He held the chair of auxiliary historical sciences at Marburg (1902-1904), then taught history at Giessen (until 1913) and at Tübingen.
A profound scholar of medieval and modern history, he gained renown with the publication of sources on the Council of Basel (*Concilium basileense. Studien und Quellen zur Geschichte des Konzils von Basel*, 5 vols., Basel 1896-1904). His fundamental work, however, is the history of the papacy as both an idea and a reality through the centuries, extending to the time of Innocent III (*Das Papsttum. Idee und Wirklichkeit*), of which the first volume appeared in Stuttgart in 1934, followed by the two parts of the second volume in 1938 and 1939. Author of notable syntheses (*Die Epochen der deutschen Geschichte*, Stuttgart 1923; *Tausend Jahre deutsch-französische Beziehungen*, ibid. 1930), among his later studies are to be recalled: *Piero da Monte, ein Gelehrter und päpstlicher Beamter des 15. Jahrhunderts* (Rome 1941), and *Pseudoisidors erstes Auftreten im deutschen Investigativstreit* (in *Studi gregoriani*, II, Rome 1947, pp. 91-101).