Mauretania was an ancient African area which included most of present day northern Morocco and western Algeria. It was not coterminous with modern Mauritania. It was settled by Berber tribes who did not have an overarching ruler, but after the Punic wars it fell under Roman influence. In 25 BC Augustus made Juba II its ruler, and later Claudius divided it into two provinces: Mauretania Caesariensis, with Caesariensis (modern Cherchel) as the capital; and Mauretania Tingitana, with Tingis (present day Tangiers) as capital. Roman control continued until the fifth century AD, when native chieftains finally took over.
Mauretania was also the name of a famous luxury liner, sister ship to the Lusitania of the British Cunard Line. The Mauretania was launched in 1906 and made her maiden voyage from Liverpool to New York in 1907. The Mauretania featured a new steam turbine engine which helped her to set a number of Blue Riband records, the first on the return leg of that maiden trip. (The trip took less than 6 days.) During World War I Mauretania was used as a troop and hospital ship. In 1921 she was refitted, including a conversion from coal to oil, and continued her transantlantic service. Her last Atlantic crossing took place in 1934, and she was scrapped in 1935. In 1938 a second Mauretania was launched; another Cunard ship, this one shared with her predecessor a luxurious style and level of service. Her maiden voyage too was from Liverpool to New York, and she too was pressed into service during World War II. She too later returned to civilian duty, and was sold for scrap in 1965.
Mauretania is also an early Starfleet ship class.
There's a glowing account of the first Mauretania ship at
http://uncommonjourneys.com/pages/mauretania/mauretania.htm
and the second at
http://members.aol.com/bry1976/mauretania/
and the starship at
http://www.ex-astris-scientia.org/my_ships/mauretania.htm