Peninsular and Oriental Steam Navigation Co
of 122 Leadenhall Street, London.
1822 Brodie McGhie Willcox and Arthur Anderson proposed a steamer service to India. The Governor of Calcutta, Lord Amherst, promised a reward for the first journey in less than 70 days.
1837 the Peninsular Co was founded by Bourne in association with Arthur Anderson, Sir John Campbell, Francis Carleton, Joseph C. Ewart, Capt Samuel Thornton, Robert Thurburn, Brodie M'Ghie Willcox, James Hartley, Charles Wye Williams and Peter John De Zulueta and received a contract from the British government for a mail service from Falmouth to Gibraltar.
1837 Won contract from the British government to carry mail from London to Spain and Portugal
1837 the Governor-General of India, Lord William Bentinck, asked Willcox and Anderson if they could establish a service from Suez to India.
1840 Second government contract to Alexandria. The Peninsular and Oriental Steam Navigation Company was incorporated by royal charter. 
1840 Bought a small river boat for the Nile called the Lotos which was fitted with oscillating engines by John Penn. The tests were inspected by Captain Bourne and his son, John Bourne, on behalf of the company, which then ordered 3 sea-going vessels using that type of engine. Another company vessel on the Nile was the Cairo.
1842 Connected to/from India by means of an overland journey to Port Suez and thence by ship.
1845 P&O services were extended to Singapore and the Far East
1852 Bi-monthly Singapore to Australia service.
1853 Southampton - Capetown - Australia sailings were started.
Crimea War - the company played a major role in transporting troops to the Crimea
1860 The SS Mooltan was built for Peninsular and Oriental Steam Navigation Co by Thames Ironworks and Shipbuilding Co with compound engines by Humphrys, Tennant and Co, making P&O the second shipping company to use them. Humphrys, Tennant and Co supplied compound engines for many of the company's ships
When the Suez Canal opened, the company found it had the wrong type of ships so it had to order larger and faster ships to stay competitive
1904 The company began cruising as a response to falling passenger numbers in the traditional low season for liner voyages. The Company invested heavily in the new venture but by 1910 the income from the touring business was still showing a poor return
1910 Purchased the fleet and goodwill of the Blue Anchor Line which became the P&O Branch Line providing an alternative route to Australia, via Africa and the Cape, greater cargo capacity and a new and different class of passenger.
1914 the Australasian United Steam Navigation Company. Amalgamated with British India Steam Navigation Co.
1920 Purchased the General Steam Navigation Co.
1922 Loss of The Egypt. 
1926 Mr R. T. Clarke appointed as Superintendent-Engineer
1930 See P and O Tours
1935 Acquired Moss Hutchinson Line.
1958 Formed the trans-Pacific service which was called the Orient and Pacific Line.
1971 Major restructuring of the P&O Group into "operating divisions". The P&O General Cargo division was formed to operate the cargo ships as one fleet including the remaining cargo liners and passenger/cargo ships in the Indian Ocean and the Gulf; the educational cruising was operated by the new Passenger Division.
1972 the Strick Line was purchased
1974 Acquired Bovis, a diversification of interests outside shipping.
1974 Princess Cruises was purchased.
1983 in the face of a hostile bid from Trafalgar House Plc, salvation lay in further diversification and a merger with Sterling Guarantee Trust.
The Company's interests expanded into a wide variety of non-shipping activities including housebuilding, oil exploration, road haulage, exhibition centres and Barrier Reef resorts. P&O's passenger fleet was focused on cruising and bulk carriers; container ships replaced the old cargo trades.
1990s Port operations in and around Australia and Logistics became an increasingly important focus as the company sold many of its "non-core" assets.
2000 P&O's cruising operations were demerged in October 2000 as an independent company, P&O Princess Cruises, which was later acquired by Carnival Corporation in 2003.
2005 P&O's last interests in the container shipping joint venture, P&O Nedlloyd, was sold to Maersk.
2006 P&O was one of the largest port operators in the world; together with P&O Ferries, P&O Ferrymasters, P&O Maritime Services, P&O Cold Logistics and its British property interests, the company was acquired by DP World.