Question: When did the country that Sanath Nandasiri is from leave the British Empire?

full_context: Document 1: Sri Lankan independence movement: The Sri Lankan independence movement was a peaceful political movement which aimed at achieving independence and self - rule for Sri Lanka, then Ceylon, from the British Empire. It was initiated around the turn of the 20th century and led mostly by the educated middle class. It succeeded when, on February 4, 1948, Ceylon was granted independence as the Dominion of Ceylon. Dominion status within the British Commonwealth was retained for the next 24 years until May 22, 1972 when it became a republic and was renamed the Republic of Sri Lanka.
Document 2: Sammu Raghu De Silva Chandrakeerthy: Prof. Sammu Raghu De Silva Chandrakeerthy was born in 1945 and had his schooling at Richmond College, Galle. He entered the Faculty of Engineering of the University of Ceylon at Peradeniya in 1963 and graduated in 1967 with an Honours Degree in Civil Engineering. He obtained the PhD degree specializing in Structural Engineering in 1973, from the University of Sheffield, England.
Document 3: Sinha Basnayake: Son of the prominent lawyer Hema Henry Basnayake, QC; he was educated at the Royal College, Colombo and graduated with a first class in law from the University of Oxford. After qualifying as a barrister he joined the UN as a Legal Officer in the International Trade Law Branch of the Office of Legal Affairs, eventually becoming its Director. Appointed as a President's Counsel by the government of Sri Lanka, he has served in many committees of the UN.
Document 4: History of India: From 1920 leaders such as Mahatma Gandhi began highly popular mass movements to campaign against the British Raj using largely peaceful methods. The Gandhi-led independence movement opposed the British rule using non-violent methods like non-cooperation, civil disobedience and economic resistance. However, revolutionary activities against the British rule took place throughout the Indian subcontinent and some others adopted a militant approach like the Indian National Army that sought to overthrow British rule by armed struggle. The Government of India Act 1935 was a major success in this regard. All these movements succeeded in bringing independence to the new dominions of India and Pakistan on 15 August 1947.
Document 5: Dominion of Ceylon: Between 1948 and 1972, Ceylon was an independent country in the Commonwealth of Nations that shared a monarch with Australia, Canada, New Zealand and the United Kingdom, and certain other sovereign states. In 1948, the British Colony of Ceylon was granted independence as Ceylon. In 1972, the country became a republic within the Commonwealth, and its name was changed to Sri Lanka. It was an island country in South Asia, located about 31 kilometres (19.3 mi) off the southern coast of India.
Document 6: Second Sirimavo Bandaranaike cabinet: The Second Sirimavo Bandaranaike cabinet was the central government of Ceylon led by Prime Minister Sirimavo Bandaranaike between 1970 and 1977. It was formed in May 1970 after the parliamentary election and it ended in July 1977 after the opposition's victory in the parliamentary election. The second Sirimavo Bandaranaike cabinet saw Ceylon severing the last colonial ties with Britain as the country became a parliamentary republic in May 1972. The country was also renamed Sri Lanka.
Document 7: Kularathna Maha Vidyalaya: Kulrathna Maha Vidyalaya also known as P. De S. Kularathna Vidyalaya is a mixed school in Ambalangoda, Sri Lanka. The school was established in 1986 by Dayawansha Ginige who was the founder principal of the school. The school is named after the famous Sri Lankan educationist Patrick de Silva Kularatne. Presently Kulrathna Maha Vidyalaya provides primary and secondary education to a student population of over 3000.
Document 8: Sanath Nandasiri: Professor Sanath Nandasiri (; born February 15, 1942 in Gothatuwa, Sri Lanka) is a Sri Lankan classical musician. He is the current Chancellor of the University of the Visual and Performing Arts in Sri Lanka. President Maithripala Sirisena appointed Nandasiri after the death of Pandit Amaradewa.
Document 9: D. S. Senanayake: Don Stephen Senanayake (; ; 21 October 1883 – 22 March 1952) was a Sri Lankan statesmen. He was the first Prime Minister of Sri Lanka having emerged as the leader of the Sri Lankan independence movement that led to the establishment of self-rule in Sri Lanka. He is considered as the "Father of the Nation".
Document 10: Sri Lanka Matha: There are differing accounts as to the origin of the Sri Lanka Matha. The most widely held view is that Sri Lankan composer Ananda Samarakoon wrote the music and lyrics to the song inspired / influenced by Bengali poet Rabindranath Tagore. A minority suggest that Tagore wrote the anthem in full. Some have suggested that Tagore wrote the music whilst Samarakoon wrote the lyrics. Samarakoon had been a pupil of Tagore at Visva - Bharati University, Santiniketan. After returning to Ceylon Samarakoon taught music at Mahinda College, Galle. The song, which was then known as Namo Namo Mata, was first sung by students at Mahinda College. After it was sung by the choir from Musaeus College, Colombo at a public event it became hugely popular in Ceylon and was widely played on radio.
Document 11: Senate of Ceylon: The Senate was the upper chamber of the parliament of Ceylon (now Sri Lanka) established in 1947 by the Soulbury Commission. The Senate was appointed and indirectly elected rather than directly elected. It was housed in the old Legislative Council building in Colombo Fort and met for the first time on 12 November 1947. The Senate was abolished on 2 October 1971 by the eighth amendment to the Soulbury Constitution, prior to the adoption of the new Republican Constitution of Sri Lanka on 22 May 1972. In 2010 there were proposals to reintroduce the Senate.
Document 12: Sri Lanka Matha: There are differing accounts as to the origin of the Sri Lanka Matha. The most widely held view is that Sri Lankan composer Ananda Samarakoon wrote the music and lyrics to the song inspired / influenced by Bengali poet Rabindranath Tagore. A minority suggest that Tagore wrote the anthem in full. Some have suggested that Tagore wrote the music whilst Samarakoon wrote the lyrics. Tagore being directly involved in the creation of the song has been denied by some historians like Indian Lipi Ghosh and Sri Lankan Sandagomi Coperahewa. Samarakoon had been a pupil of Tagore at Visva - Bharati University, Santiniketan. After returning to Ceylon Samarakoon taught music at Mahinda College, Galle. The song, which was then known as Namo Namo Mata, was first sung by students at Mahinda College. After it was sung by the choir from Musaeus College, Colombo at a public event it became hugely popular in Ceylon and was widely played on radio.
Document 13: British Empire: Britain's remaining colonies in Africa, except for self-governing Southern Rhodesia, were all granted independence by 1968. British withdrawal from the southern and eastern parts of Africa was not a peaceful process. Kenyan independence was preceded by the eight-year Mau Mau Uprising. In Rhodesia, the 1965 Unilateral Declaration of Independence by the white minority resulted in a civil war that lasted until the Lancaster House Agreement of 1979, which set the terms for recognised independence in 1980, as the new nation of Zimbabwe.
Document 14: S. Mahinda: S. Mahinda arrived in Ceylon (now Sri Lanka) at a young age and was ordained as a Buddhist monk. Having learned the Sinhala language, he became a poet, creating several literary works inspiring patriotism among the Sinhalese and urging them to fight for their freedom during Sri Lankan Independence movement.. He is now considered a national hero of Sri Lanka and one among the greatest of Sinhalese poetry figures of all time.
Document 15: Siri Gunasinghe: Siri Gunasinghe was born Ruwanwella in Kegalle District of Sri Lanka. He was educated at Mahinda College, Galle and University of Ceylon. He subsequently travelled to Paris where he continued his studies and wrote "La technique de la peinture indienne d'après les textes du Silpa". Later Siri Gunasinghe became a university lecturer and taught at the University of Peradeniya, Sri Lanka and at the University of Victoria, British Columbia, Canada where he was a Professor in the Department of History in Art. Siri Gunasinghe had lived in Canada since 1970.
ground_truth: February 4, 1948
sub_queries: What country is Sanath Nandasiri from? Answer: Sri Lanka
when did Sri Lanka leave the british empire Answer: February 4, 1948