Education
He studied at the University of Copenhagen.
He studied at the University of Copenhagen.
He spent three years (1845-1848) researching at the archives of England, France, the Netherlands, Italy and Germany. Upon completion of this task, he returned to Denmark. In 1851 he became a lecturer at the University of Copenhagen and, in 1862, a professor of history and northern archaeology.
His principal work is his De Tre Nordiske Rigers Historie, 1497-1536, ("The History of the Three Northern Kingdoms," five volumes, 1864-1872).
He wrote the work following years of examinations of the archives of European nations.