Formed on December 11, 1866, by the merger of the three largest Danish steamship companies, under the leadership of financier Carl Frederik Tietgen.27 Began operations on January 1, 1867, with 19 ships, based in Copenhagen.27 Initial routes included domestic services in Denmark and international services to Norway, the Baltic, Belgium, United Kingdom (including Harwich from 1880), Iceland, and the Faroe Islands.27 Expanded rapidly, adding routes to Sweden, France, the Mediterranean, Black Sea, North America, and South America.27 In the 1880s, became one of the world's ten largest shipping companies by number of ships.27 In 1898, acquired Dampskibsselskabet Thingvalla, creating the Scandinavian-American Line for transatlantic service, which operated until 1935.27 Suffered significant ship losses during World War I and II (31 ships lost in WWII, plus 3 to mines after the war).27 Many ships were requisitioned by the Allies or Germany during WWII.27 After the war, rebuilt its fleet and reopened routes, introducing concepts like "door-to-door" container transport in 1950 and entering the "cross-trading" market (routes without calls in Denmark) with the Nordana Line in 1957.55 Continued to operate and expand after 1950, acquiring other companies like Tor Line.55 Notable pre-1950 ships include Thingvalla, Hekla, Oscar II, Frederik VIII, Parkeston, J.C. la Cour, C.F. Tietgen, Kronprins Olav.