Started by Joseph Marsh in 1835,[5] it was established as the Colombo Academy by Sir Robert Wilmot-Horton in January 1836, as part of the implementation of the recommendations of the Colebrooke Cameron Commission (1833), and was the first government-run secondary school for boys[6] in the country.

As a national school, it is funded by the government as opposed to the provincial council providing both primary and secondary education.

[16] The school has produced many distinguished alumni, among whom are presidents of two countries,[17] a sultan,[18] and four prime ministers.

[17] Situated in Cinnamon Gardens, a residential suburb of Colombo, it occupies an area of 15.6 hectares (39 acres) (with the sports complex) along the Rajakeeya Mawatha, bordered by Reid Avenue to the east; Kumarathunga Munidasa Mawatha (formally Thurstan Road) to the west and to the south its former premises, which now houses the Department of Mathematics of the University of Colombo.

The administration of the college hostel is carried out by the warden under the supervision of the principal and is assisted by a sub-warden.

Another memorial plaque is displayed in the entryway to the Navarangahala, bearing the names of 47 Old Royalists who were killed in action in the civil war.

[24] Then in the following year in 1836, Sir Robert Wilmot-Horton, the British Governor of Ceylon, based on the recommendations of the Colebrooke Commission, established the Colombo Academy,[7] as an English public school modeled on Eton College, with Marsh continuing as headmaster on government pay.

[27] In 1836 the school was moved to San Sebastian Hill, Pettah, (prior to which it was at Maradana, next to Hulftsdorp); it would stay there for another 75 years before being shifted to Thurstan Road.

[28] In 1865 the Morgan Committee of inquiry into education recommended that it be reorganized and that scholarships should be awarded to study at the University of Oxford,[7] and as a result in 1869, Queen's College was amalgamated with the Colombo Academy.

The Gazette notification giving Her Majesty's approval to change the name of the school appeared on 31 July 1881.

[32] Ten years later on 10 October 1923, the school moved, this time to the newly constructed Victorian styled building further down Reid Avenue, which it continues to occupy.

Five years earlier on 22 May 1972, the members of the House of Representatives of the Dominion of Ceylon met at the Royal Primary School Hall (Navarangahala) and enacted the Republican Constitution that established the Republic of Sri Lanka.

The college's motto is Disce aut Discede, meaning "learn or depart" in Latin.

"Floreat", meaning "flourish" in Latin, has been a motto associated with the school since the founding of the Colombo Academy in 1836.

It is derived from "Floreat Etona", the motto of Eton College on which the academy was modeled on at its formation.

In addition to the teachers, four categories[36] of senior boys are entitled to maintain school discipline.

Boys who belong to the most senior category of student leaders prefects wear a silver college crest on their all-white uniform.

Formally four houses were established in 1918 by Principal Hartley with the names Cinnamon Gardens, Bambalapitiya North and South, and Colpetty.

Taking centre stage of the annual sporting calendar is the Royal-Thomian (Big Match), the Bradby and the Regatta.

[40] The original match was played between Colombo Academy and S. Thomas' College, Mutwal Modara in 1879, with schoolmasters participating as well as schoolboys.

This is preceded by the Cycle Parade which usually happens on the day before the big match, with the official objective of visiting the captain's house to encourage him.

By 1966, it broadened out to give rise to the regatta having a card of six events, made up of 2 Single Sculls, 2 Coxless Pairs and 2 Coxed Fours.

In 2007, under the captaincy of Maalik Aziz, Royal won the regatta with a record 40 points to nil, for the first time in its history.

[51] Organized by the Adventure Club, students have undertaken several expeditions: The college has a strong association with the study of music, both western and oriental.

The annual musical festival SAGA organized by the School Development Society with the assistance of alumni has become an important event on Colombo's cultural calendar.

[54] Productions are staged regularly by alumni, organized by the Old Royalists Association of Dramatists and the Royal College Union.

The college magazine dates back to 1837[56] when The Colombo Academy Miscellany and Juvenile Repository was published on a monthly basis[56] during the time of headmaster Rev.

The school has produced the 1st Executive President of Sri Lanka, J. R. Jayewardene; the 9th Executive President, Ranil Wickremesinghe; the last Sultan of the Maldives, Muhammad Fareed Didi;[18] and four Prime Ministers of Sri Lanka, including General Sir John Kotelawala, J. R. Jayewardene, Ranil Wickremesinghe, and Dinesh Gunawardena, as well as the first Ceylonese Acting Governor, Sir James Peiris.

The school's alumni also include Shirley Amerasinghe (President of the United Nations General Assembly), Gamani Corea (Secretary-General of the UNCTD), Christopher Weeramantry (Vice President of the International Court of Justice), Sir Nicholas Attygalle (first Sri Lankan vice chancellor), V. K. Samaranayake (founder of the UCSC), Mohan Munasinghe (Vice Chairman of the IPCC) and General Deshamanya Sepala Attygalle (first Sri Lankan four-star general).

Annually the RCU organizes many sporting events including the Royal-Thomian, the Bradby Shield Encounter, the Royal Thomian Regatta, as well as national initiatives such as EDEX (the biggest educational fair in the island) and carrying out development projects for the college.