A choirboy is a boy member of a choir, also known as a treble.
As a derisive slang term, it refers to a do-gooder or someone who is morally upright, in the same sense that "Boy Scout" (also derisively) refers to someone who is considered honorable.
The use of choirboys in Christian liturgical music can be traced back to pre-Christian times. Saint Paul's dictum that "women should be silent in churches" (mulieres in ecclesiis taceant) resonated with this largely patriarchal tradition; the development of vocal polyphony from the Middle Ages through the Renaissance and Baroque thus took place largely, though not exclusively, in the context of the all-male choir, in which all voice parts were sung by men and boys.
The first known usage in print of the term "choirboy" (rather than the earlier "singing boy") was by the Victorian novelist William Makepeace Thackeray (1811–1863) in Chapter Vii of his story The Ravenswing, published in Fraser's Magazine for Town and Country (London, Sept. 1843, XXVIII/165, p. 321): "He had been a choir-boy at Windsor".
In more recent years as girls have begun joining formerly all-male choirs, the gender-neutral term chorister is more often being used instead.  (Until the late 20th century chorister was sometimes applied to adult choral singers too, but is now limited to children.)
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Boys are generally eligible to join a choir at the age of seven. Voice trials are part of the selection process for larger choirs and tend to measure the quality of voice and pitch recognition rather than singing experience. Boys that are accepted into a choir begin as probationers.
Extensive musical training is provided, in particular for cathedral choristers. A number of famous composers and musicians began their careers as choristers. In 1740, Joseph Haydn was sent at the age of eight to Vienna to become a choirboy at Saint Stephen's Cathedral. Franz Schubert was accepted into the choir of the Imperial Court Chapel in 1808 when he was 11. Dudley Moore became a choirboy at six.
A small bursary is paid to the boys each term, and opportunities arise for other bonuses during the year. 
The Royal School of Church Music (RSCM) organized the first UK competition for Choirboy of the Year in 1975. It was sponsored by Rediffusion and received more than 2,500 entries. The final, which took place in St George's, Hanover Square, London, was won by Matthew Billsborough. He sang the St. Matthew Passion by Bach. The last RSCM national competition was held in 1992, and was won by Gavin Moralee (now known as Gavin Cranmer-Moralee). He sang The Monk and his Cat by Samuel Barber and How Beautiful are the feet from Handel's Messiah.
The competition was open only to boy choristers up until 1986 when the BBC first organized an additional separate competition for girl choristers through the age of 16. The two competitions ran side-by-side for three years before the RSCM competition began including girls in its own competitions, naming both a choirboy and choirgirl of the year. From 1989 to 1992, both the BBC and RSCM named a different girl as Choirgirl of the Year.
The winner of 1995 BBC Choirgirl of the year was Tabitha Watling. In it, she was also competing against Katherine Jenkins. 
In 1998, BBC Radio 2 began hosting a combined boys and girls competition, without any other simultaneous competitions. James Fox, from St. Mary's Warwick, was named Choirboy of the Year and Eloise Irving, from West Sussex, was named Choirgirl of the Year. The format has remained the same through the most recent competition. 
Thomas Jesty  was BBC Young Chorister of the Year 2004.  Both he and Harry Sever (the 2003 winner) had solos on the December 2004 album "Hear My Prayer".  They also took part in the United Kingdom's biggest fundraising concert in aid of the victims of the 2004 Boxing Day tsunami. 
The 2005 winners of the competition were Laura Wright (15) from Suffolk and Sam Adams-Nye from Bristol. 
The 2007 winners of the BBC Radio 2 Young Chorister of the Year competition were twelve-year-old Joel Whitewood of Canterbury Cathedral and 15-year-old Charlotte Louise McKechnie of Giffnock South Church in Scotland. The finals were held at St Paul's Cathedral in London and hosted by Aled Jones.
The 2008 winners of the BBC Radio 2 Young Chorister of the Year competition were twelve-year-old Harry Bradford of the Chapel Royal, St. James's Palace, London and 14-year-old Alice Halstead  of St. Alphege's Church, Solihull.  The finals were held at St Paul's Cathedral in London and hosted by Charles Hazlewood. 
In 2011 Richard Decker of the Queen's Chapel of the Savoy and St Olave's Grammar School was awarded chorister of the year.  The 2012 winners of the BBC Radio 2 Young Chorister of the Year competition were thirteen-year-old Isaac Waddington  of the Choir of Chichester Cathedral, West Sussex and 15-year-old Louisa Stirland. The finals were held at St Martin in the Fields and hosted by Aled Jones.
A boy soprano or boy treble is a young male singer with an unchanged voice in the soprano range, a range that is often still called the treble voice range when talking about children.
Aled Jones, is a Welsh singer and radio and television presenter. As a teenage chorister, he reached widespread fame during the mid-1980s. Since then he has worked in television with the BBC and ITV, and radio.
Anthony Way is an English chorister and classical singer, who rose to fame after appearing as a chorister in a BBC TV series. He has since had success as a recording artist, with gold and platinum discs to his credit.
The Royal School of Church Music (RSCM) is a Christian music education organisation dedicated to the promotion of music in Christian worship, in particular the repertoire and traditions of Anglican church music, largely through publications, training courses and an award scheme. The organisation was founded in England in 1927 by Sir Sydney Nicholson and today it operates internationally, with 8,500 members in over 40 countries worldwide, and is the largest church music organisation in Britain.
Barry Michael Rose OBE FRAM FRSCM HonFRCO is a choir trainer and organist. He is best known for founding the choir and the pattern of daily sung worship at the new Guildford Cathedral in 1961, as well as directing the music at the 1981 wedding of Charles, Prince of Wales and Diana, Princess of Wales at St Paul's Cathedral in London.
The Cathedral of St Mary and St Helen is a Roman Catholic cathedral in Brentwood, Essex, England. It is the seat of the Diocese of Brentwood.
The Choirboys was an English boy band, made up of cathedral choristers. In 2005, a talent search was held to find a young chorister to bring choral music into the current music scene. However, the judges could not decide which of the three finalists should be given the recording contract and decided to assemble them as a trio.
Paul Miles-Kingston, is a British singer who achieved fame as a boy soprano classical singer.
The Land of Lakes Choirboys is a nonprofit boy choir organization based in Elk River, Minnesota. Consisting of four individual choir ensembles, the organization performs in local, national, and international locations. Through a series of training programs, choristers are taught arts of music, leadership, respect, honor and other elements of human integrity. Known for singing works of various musicians such as Bach and Antonio Vivaldi, the choristers sing religious and secular music.
Simon Lole is well known as a choral director, organist, composer, arranger and broadcaster. He was organist of Barking Parish Church (1978–80), Croydon Parish Church (1980–85), Director of Music at St Mary's Church, Warwick (1985–94) before becoming Organist and Director of Music at Sheffield Cathedral (1994–1997) and then at Salisbury Cathedral (1997–2005), He spent two periods as Acting Director of Chapel Music at Jesus College, Cambridge. He has composed over 60 published works. Best known are "The Father's Love" (RSCM), "The Journey" (RSCM), "I am the bread of life" (RSCM),"Shall we not Love Thee, Mother dear?" (RSCM), "The St David's Service" (Encore), Angels (Banks) and "Jesu, the very thought of Thee" (OUP). Much of his music has been recorded and broadcast on radio and TV. He is now Director of Music at St Mary's Church, Swanage.
The Metropolitan Cathedral Church of St David, also known as St David's Cathedral, Cardiff, is a Roman Catholic cathedral in the city centre of Cardiff, Wales, and is the centre of the Roman Catholic Archdiocese of Cardiff. Located in Charles Street, the cathedral remains the focal point for Catholic life in Cardiff, and the country as a whole. It is one of only three Roman Catholic cathedrals in the United Kingdom that is associated with a choir school.
Leeds Minster, or the Minster and Parish Church of Saint Peter-at-Leeds is the minster church of Leeds, West Yorkshire, England. It stands on the site of the oldest church in the city and is of architectural and liturgical significance. A church is recorded on the site as early as the 7th century, although the present structure is a Gothic Revival one, designed by Robert Dennis Chantrell and completed in 1841. It is dedicated to Saint Peter and was the Parish Church of Leeds before receiving the honorific title of "Minster" in 2012. It has been designated a Grade I listed building by Historic England.
The Choir of Leeds Minster is the choir of Leeds Minster, Leeds, England, which became a Minster in September 2012. The choir was founded by vicar, Richard Fawcett probably as early as 1815, and was certainly in existence by 1818. The church's choir - boys and men - was, from its origins, a charge on the church rate; and, in what was then a largely non-conformist town, a none-too-popular one. By the 1830s, the choir's resourcing had been taken over by a list of voluntary subscribers. On arrival as Vicar of Leeds in 1837, Walter Farquhar Hook said he found "the surplices in rags and the books in tatters". Additional to its extensive commitment in the provision of choral services, the choir is known to a wide public through many recitals, recordings and broadcasts and by its regular choir tours - the first tour was held in July 1968 and the 40th anniversary tour, from 22 to 27 July 2008, included singing in Ely Cathedral, King's College, Cambridge, the National Musicians' Church St Sepulchre-without-Newgate in the City of London, All Saints Pastoral Centre London Colney and the Chapel of the Royal Hospital Chelsea.
Alice Halstead is a London-based soprano.
The Choir of Salisbury Cathedral exists to sing services in Salisbury Cathedral, Wiltshire, England, and has probably been in existence since the consecration of the cathedral in 1258.
Winchester Cathedral Choir is an internationally recognized professional choir based at Winchester Cathedral at Winchester in Hampshire. The choir currently consists of 18 boy choristers and 12 lay clerks and sings eight services weekly in the Cathedral. Additionally, 20 girl choristers sing one service a week as well as concerts. Sometimes the group augments their numbers when certain musical works require a greater number of voices. The group's choristers all attend The Pilgrims' School where they study singing, music theory, music history, and at least one instrument in addition to general academic studies. The choir regularly tours internationally, has produced numerous recordings, and appears often in television and radio broadcasts. The choir is currently directed by Andrew Lumsden, who assumed the post in 2002.
Isabel Suckling is a British singer who, upon signing a record deal with Decca Records, became the youngest classical recording artist signed by Decca, and the first choirgirl to sign a record contract with a major music label. Suckling sang in the choir at York Minster at the time, and was discovered by Decca following a nationwide search. She was mentored by the singer, TV/radio presenter and former boy soprano Aled Jones.
St John's College is an independent co-educational day school in the village of Old St Mellons in Cardiff, Wales. It is the choir school of Wales' national Catholic cathedral, Cardiff Metropolitan Cathedral.
Lichfield Cathedral School is an independent day school in the city of Lichfield, Staffordshire, England. It traces its lineage to the 14th century when Lichfield Cathedral made provisions to educate its choristers. The school in its current form now educates over 400 boys and girls from nursery to sixth form. While the school still serves its primary purpose of educating choristers of the cathedral, it is open to pupils of all faiths.
Nigel McClintock is a Northern Irish organist, choral conductor and teacher. He was previous director of music at Croydon Parish Church.