RMS Mauretania was an ocean liner designed by Leonard Peskett and built by Wigham Richardson and Swan Hunter for the British Cunard Line, launched on the afternoon of 20 September 1906. She was the world's largest ship until the launch of RMS Olympic in 1910. Mauretania became a favourite among her passengers. She captured the eastbound Blue Riband on her maiden return voyage in December 1907, then claimed the westbound Blue Riband for the fastest transatlantic crossing during her 1909 season, which she held both speed records for 20 years.The ship's name was taken from the ancient Roman province of Mauretania on the northwest African coast, not the modern Mauritania to the south. Similar nomenclature was also employed by Mauretania's running mate Lusitania, which was named after the Roman province directly north of Mauretania, across the Strait of Gibraltar in Portugal. Mauretania remained in service until September 1934, when Cunard-White Star retired her; scrapping commenced in Rosyth, in 1935.

Cunard Line () is a British cruise line based at Carnival House at Southampton, England, operated by Carnival UK and owned by Carnival Corporation & plc. Since 2011, Cunard and its three ships have been registered in Hamilton, Bermuda.In 1839, Samuel Cunard was awarded the first British transatlantic steamship mail contract, and the next year formed the British and North American Royal Mail Steam-Packet Company in Glasgow with shipowner Sir George Burns together with Robert Napier, the famous Scottish steamship engine designer and builder, to operate the line's four pioneer paddle steamers on the Liverpool–Halifax–Boston route. For most of the next 30 years, Cunard held the Blue Riband for the fastest Atlantic voyage. However, in the 1870s Cunard fell behind its rivals, the White Star Line and the Inman Line. To meet this competition, in 1879 the firm was reorganised as the Cunard Steamship Company, Ltd, to raise capital.In 1902, White Star joined the American-owned International Mercantile Marine Co. In response, the British Government provided Cunard with substantial loans and a subsidy to build two superliners needed to retain Britain's competitive position. Mauretania held the Blue Riband from 1909 to 1929. Her running mate, Lusitania, was torpedoed in 1915 during the First World War.

In 1919, Cunard relocated its British homeport from Liverpool to Southampton, to better cater for travellers from London. In the late 1920s, Cunard faced new competition when the Germans, Italians and French built large prestige liners. Cunard was forced to suspend construction on its own new superliner because of the Great Depression. In 1934, the British Government offered Cunard loans to finish Queen Mary and to build a second ship, Queen Elizabeth, on the condition that Cunard merged with the then ailing White Star line to form Cunard-White Star Line. Cunard owned two-thirds of the new company. Cunard purchased White Star's share in 1947; the name reverted to the Cunard Line in 1950.Upon the end of the Second World War, Cunard regained its position as the largest Atlantic passenger line. By the mid-1950s, it operated 12 ships to the United States and Canada. After 1958, transatlantic passenger ships became increasingly unprofitable because of the introduction of jet airliners. Cunard undertook a brief foray into air travel via the "Cunard Eagle" and "BOAC Cunard" airlines, but withdrew from the airliner market in 1966. Cunard withdrew from its year-round service in 1968 to concentrate on cruising and summer transatlantic voyages for holiday makers. The Queens were replaced by Queen Elizabeth 2 (QE2), which was designed for the dual role.In 1998, Cunard was acquired by the Carnival Corporation, and accounted for 8.7% of that company's revenue in 2012. In 2004, QE2 was replaced on the transatlantic runs by Queen Mary 2 (QM2). The line also operates Queen Victoria (QV) and Queen Elizabeth (QE). As of 2019, Cunard is the only shipping company to operate a scheduled passenger service between Europe and North America.