Charles was born in Stavanger, the fifth son of Arndt Leonard Thesen (26 October 1816 – 24 June 1875), a wealthy and respected man in the town. The German-Danish War of 1864–67 caused a downturn in trade and shipping, and in 1868 caused the collapse of several companies in Stavanger, among which was "A.L. Thesen &amp; Co."