Background
He was born in Christiania as a son of military officer and businessman Truels Nicolaisen Drolsum (c1821–1892) and his wife Christine E. Knudsen (1821–1909).
He was born in Christiania as a son of military officer and businessman Truels Nicolaisen Drolsum (c1821–1892) and his wife Christine E. Knudsen (1821–1909).
He instead studied Old Norse, and after four years of working with source texts he was hired by Ludvig Ludvigsen Daae at the University Library of Oslo.
His eyesight prevented him from becoming a military officer like he wanted to, and after his examen artium in 1864 he also ruled out law studies. Together with Daae he edited the six-volume work on global history, Illustrert Verdenshistorie released between 1876 and 1880. He was promoted to chief librarian in 1876, and remained so until 1922.
He worked to improve the library, and between 1911 and 1913 the building which is today the National Library of Norway was raised.
He also worked for reinstating the legal deposit, greatly improving the library"s collections. The endeavor was successful as the Parliament of Norway passed the act Lov om Afgivelse af Tryksager til Bibliotheket in 1882.
He was a popular speaker and wrote articles in the press Collections of his agitative works were published as Foreign Norges Sag.
Ti Aars Arbeide. Afhandlinger og Foredrag 1885–1895 in 1896 and Foreign Norges Sag.
Ny Samling. Tyve Aars Arbeide. Afhandlinger og Foredrag 1895–1916 in 1917. He died in September 1927 in Oslo.
He was a member of the pro-military association Norges Forsvarsforening, and chaired the executive committee of its Kristiania branch from 1889 to 1915.