Question: Several ships have borne the name Duke of Clarence, named for one or another Duke of Clarence, originally Prince William, the first Duke of Clarence and St Andrews, who acceded to the throne as William IV of the United Kingdom, was King of the United Kingdom of Great Britain and Ireland and King of Hanover from 26 June 1830 until when?
Context: Duchess of Rothesay is a Scottish courtesy title.  It is held by the wife of the Duke of Rothesay since the first Duke in 1398.  Due to the mortality rate and the fact that very few Dukes of Rothesay were of majority or married prior to ascending the throne (if that), there have in fact been only eight Duchesses of Rothesay.  A separate Scottish throne has not existed "de facto" since 1603 when James VI of Scotland acceded to the throne of England when the House of Tudor died out, creating a personal union.  The Act of Union of 1707 united de jure the separate kingdoms and thrones into the Kingdom of Great Britain.  Ever since 1603 the title of the Duchess of Rothesay is held by the Princess of Wales, who was also the Duchess of Cornwall; the title of Duchess of Rothesay is for her use when in Scotland. William IV (William Henry; 21 August 1765 – 20 June 1837) was King of the United Kingdom of Great Britain and Ireland and King of Hanover from 26 June 1830 until his death.  The third son of George III and younger brother and successor to George IV, he was the last king and penultimate monarch of Britain's House of Hanover. Clarence is a town located in the northeastern part of Erie County, New York, United States, northeast of Buffalo.  The population was 30,673 according to the 2010 census.  This represents an increase of 17.42% from the 2000 census figure.  The Clarence census-designated place occupies the southeast part of the town and roughly corresponds to a postal district with ZIP code 14031 and 14221 in the western side which it shares with nearby Williamsville.  The town is named in honor of Prince William, Duke of Clarence and St Andrews (1765-1837), the third son of King George III and later king himself, as William IV. Princess Elizabeth of Clarence (Elizabeth Georgiana Adelaide; 10 December 1820 – 4 March 1821) was an infant member of the British royal family.  She was the second daughter and third child of Prince William, Duke of Clarence and St Andrews (later King William IV) and his wife (later Queen), Princess Adelaide of Saxe-Meiningen.  She was a granddaughter of King George III of the United Kingdom and a first cousin of Queen Victoria. Duke of Rothesay (Scottish Gaelic: "Diùc Baile Bhòid" , Scots: "Duik o Rothesay" ) is a dynastic title of the heir apparent to the British throne, currently Prince Charles.  It was a title of the heir apparent to the throne of the Kingdom of Scotland before 1707, of the Kingdom of Great Britain from 1707 to 1801, and now of the United Kingdom of Great Britain and Northern Ireland.  It is the title mandated for use by the heir apparent when in Scotland, in preference to the titles "Duke of Cornwall" (which also belongs to the eldest living son of the monarch, when and only when he is also heir apparent, by right) and "Prince of Wales" (traditionally granted to the heir apparent), which are used in the rest of the United Kingdom and overseas.  The Duke of Rothesay also holds other Scottish titles, including those of Earl of Carrick, Baron of Renfrew, Lord of the Isles and Prince and Great Steward of Scotland.  The title is named after Rothesay on the Isle of Bute, Argyll and Bute, but is not associated with any legal entity or landed property, unlike the Duchy of Cornwall. Several ships have borne the name Duke of Clarence, named for one or another Duke of Clarence, originally Prince William, the first Duke of Clarence and St Andrews, who acceded to the throne as William IV of the United Kingdom, but later the Duke of Clarence and Avondale: A clarence is a type of carriage that was popular in the early 19th century.  It is a closed, four-wheeled horse-drawn vehicle with a projecting glass front and seats for four passengers inside.  The driver sat at the front, outside the carriage.  The clarence was named after Prince William, Duke of Clarence and St Andrews, later to become King William IV of England, who died in 1837.  It was introduced in 1840 in London.  The Brougham was a lighter, two-passenger version originally commissioned by Lord Brougham. The St Andrews Trophy is a biennial men's team golf tournament contested between teams of amateur golfers representing Great Britain & Ireland and Continental Europe.  It takes its name from St Andrews in Scotland, which is colloquially known as the "Home of Golf".  The competition was founded in 1955 and first played in 1956.  It takes place in even numbered years (Great Britain & Ireland plays in the United States in the Walker Cup in odd numbered years).  It is staged alternately in Great Britain & Ireland and on the Continent, and is organised by The R&A (an offshoot of The Royal and Ancient Golf Club of St Andrews) and the European Golf Association.  The St Andrews Trophy itself was presented by the Royal and Ancient Club in 1963. Earl of Munster was a title created twice, once in the Peerage of Ireland and once in the Peerage of the United Kingdom.  The first creation came in 1789 in favour of Prince William, the third son of King George III.  He was made Duke of Clarence and St Andrews at the same time.  When William succeeded to the throne as King William IV in 1830 the titles merged with the crown. George IV (George Augustus Frederick; 12 August 1762 – 26 June 1830) was King of the United Kingdom of Great Britain and Ireland and of Hanover following the death of his father, George III, on 29 January 1820, until his own death ten years later.  From 1811 until his accession, he served as Prince Regent during his father's final mental illness.
Answer: his death