The Cunard Line lost 22 ships during the First World War. In settlement for damages caused by German military action, many of her surviving passenger ships were transferred to the British, French and American fleets to replace vessels lost. The Hamburg America Line Imperator (1913) was transferred to the Cunard fleet to replace the Lusitania, which was torpedoed in 1915 with the loss of 1,198 lives. Renamed Berengaria, she joined the Lusitania's sister ship Mauretania (1907) and Aquitania (1914) sailing out of Southampton to New York. However, by the mid-1920s Cunard's express liners were beginning to show their age, compared to new liners such as the French Line's Ile de France (1927) and the Norddeutsche Lloyd liner Bremen (1929). In 1929 Cunard began to formulate plans for a new pair of liners to regain British dominance of the North Atlantic run. The plans envisaged maintaining the same service previously operated by three ships, by building and operating ships capable of higher service speeds. The ships would need to be larger still than the existing Cunard express liners, to carry enough passengers and cargo, at high speed, for the ships to be profitable.