The Royal Mail Steam Packet Company was a British shipping company founded in London in 1839 by a Scot, James MacQueen. The line's motto was Per Mare Ubique. After a troubled start, it became the largest shipping group in the world in 1927 when it took over the White Star Line. The company was liquidated and its assets taken over by the newly formed Royal Mail Lines in 1932 after financial trouble and scandal; over the years RML declined to no more than the name of a service run by former rival Hamburg Süd.

The White Star Line was a British shipping line. Founded out of the remains of a defunct packet company, it gradually rose up to become one of the most prominent shipping companies in the world, providing passenger and cargo services between the British Empire and the United States. While many other shipping lines focused primarily on speed, White Star branded their services by focusing more on providing comfortable passages for both upper class travellers and immigrants.