3 January 1842 - the steamer Thames (I) left Falmouth for Berbice and Tay for Barbados. They were the first RMSP departures carrying mails.

The original network of mail services comprised 11 interconnecting routes, stemming from England and fanning out across the Caribbean islands and rim, and northwards to New York and Halifax NS.

9 January 1851 - The first significant expansion came from a new mail contract, carrying mails by steamer from Britain to Brazil, Uruguay and Argentina. The first departure from Southampton was on this day - Teviot (I), bound for Rio de Janeiro, where mails and passengers for Montevideo and Buenos Aires were transferred to the little screw steamer Esk (I).

1858/9 - A brief involvement in RMSP's first attempt to enter the Australian mail service, as a partner in the European and Australian RM Co. Tasmanian and Oneida entered the RMSP fleet after the company collapsed.

1864 - Expansion in the Caribbean with a mail contract to British Honduras.

2 June 1866 - Atrato (I) inaugurated the second attempt to enter the Australian mail service as a joint partner in the Panama, New Zealand & Australia RM Co (PNZA). RMSP provided sailings from Southampton to Colon, where mails were carried across the isthmus by the Panama Railroad, thence by PNZA ship across the Pacific. This, too, collapsed after a few years.

9 October 1869 - Douro (I) left Southampton this day to inaugurate a through service to Brazil and the River Plate, ending the need for a transfer at Rio de Janeiro. This established the format of South America mail services which remained until the last voyage exactly a hundred years later.

1875 - To cover non-contract services in the West Indies, RMSP was permitted to mint its own stamps for a standard mail rate of 10 cents.

1870-1900 - Years which saw little significant change, though variations to routes and schedules occurred regularly

1904 - A supplemental Royal Charter was granted which had major implications, for it allowed RMSP to acquire other companies to expand its operations.

1906 - The first sign of that expansion began this year, though it lasted only until 1909. RMSP bought the Pacific Steam Nav. Co's interest in the Orient-Pacific Line, a joint venture with Orient Line in a passenger and mail service to Australia.

1908 - RMSP acquired Forwood Line and took over that company's mail contract to Morocco.

1910-1931 - During this period of massive growth RMSP's involvement in mail services truly became the world-wide operation envisaged by the firm's founder, James Macqueen. Through companies like Pacific Steam Nav Co, Union Castle Line, Elder Dempster and White Star Line, its operations spanned the globe.

1920 - In the midst of those burgeoning decades of the 1910s and 1920s, the region where it all started - the West Indies - lost its mail service in this year. During World War I the service was curtailed as Ebro (III) and Essequibo (II) entered war service; they didn't return to the mail service, for the British Government refused any longer to subsidise an operation whose inter-island voyages for small returns were too costly. A small operation with chartered ships ended in 1920.

1932 - Following the collapse of RMSP, Royal Mail Lines (RML) was formed this year and took over the firm's mail services to South America.

1948 - RML's largest ship, Andes (II), entered the Brazil and River Plate mail service, having been involved in war work since her completion in 1939. A refurbished Alcantara (II) joined her later in the year.

1959-60 - Start of the final chapter as the South America mail service was taken over by three new ships - Amazon (III), Aragon (II) and Arlanza (II) - as replacements for Andes, Alcantara and the four Highland ships.

4 January-20 February 1969 - The last mail voyage by a Royal Mail ship, Aragon (II), took place between these dates, from London to Spain, Portugal, Canary Islands, Brazil, Uruguay and Argentina, returning to Southampton on 20 February.