Johan Ernst Welhaven Sars was a Norwegian professor, historian, author and editor. Assuming perspectives from the positivism philosophical school, his main work was Udsigt over den norske Historie, four volumes issued from 1873 to 1891. He co-edited the magazines Nyt norsk Tidskrift from 1877 to 1878, and Nyt Tidsskrift from 1882 to 1887. He was politically active for the Liberal Party of Norway and among the party's most central theoreticians.
