From 1884 to 1896, alongside first Søren Georg Møller (1834–1890) and then Søren Ludvig Tuxen (1850–1919), he was principal of Borgerdyd School in
Østerbro. Heiberg was Professor of Classical Philology at the
University of Copenhagen from 1896 until 1924 and Professor of Archeology from 1896 until 1911. He became a member of the
Royal Danish Academy of Sciences and Letters in 1893 and served as its editor in 1902–13. He was president of Rask-Ørstedfondet from 1919 until his death in Copenhagen. Among his more than 200 publications were translations of the works of
Archimedes (1880 and 1912),
Euclid (with Heinrich Menge) (1883–1916),
Apollonius of Perga (1891–93),
Serenus of Antinouplis (1896),
Ptolemy (1898/1903), and
Hero of Alexandria (1899). Many of his editions are still in use today.
Archimedes Palimpsest The Archimedes Palimpsest is a 10th-century parchment codex palimpsest. Heiberg inspected the
vellum manuscript in the library of The
Church of the Holy Sepulchre at
Istanbul in 1906, and realized that it contained mathematical works by
Archimedes that were unknown to scholars at the time. Heiberg was permitted by the Greek Orthodox Church to take photographs of the palimpsest's pages, and from these he produced transcriptions, published between 1910 and 1915 in a complete works of Archimedes. Heiberg's examination of the manuscript was with the naked eye only, while modern analysis of the texts has employed
X-ray and
ultraviolet light. The Archimedes Palimpsest is currently stored at the
Walters Art Museum in
Baltimore,
Maryland. ==Personal life==