From 1707, the Broschi family lived in the coastal city of Barletta, a few miles from Andria, but at the end of 1711, they made the much longer move to the capital city of Naples, where, in 1712 Carlo's elder brother Riccardo was enrolled at the Conservatory of S. Maria di Loreto, specialising in composition. Carlo had already showed talent as a boy singer, and was now introduced to the most famous singing teacher in Naples, Nicola Porpora. Already a successful opera composer, in 1715 Porpora was appointed maestro at the Conservatory of S. Onofrio, where his pupils included such well known castrati as Giuseppe Appiani, Felice Salimbeni, and Gaetano Majorano (known as Caffarelli), as well as distinguished female singers such as Regina Mingotti and Vittoria Tesi; Farinelli may well have studied with him privately.

Salvatore Broschi died unexpectedly on 4 November 1717, aged only 36, and it seems likely that the consequent loss of economic security for the whole family provoked the decision, presumably taken by Riccardo, for Carlo to be castrated. As was often the case, an excuse had to be found for this illegal operation, and in Carlo's case it was said to have been necessitated by a fall from a horse. Under Porpora's tuition, his singing progressed rapidly, and at the age of fifteen he made his debut a serenata by his master entitled Angelica e Medoro. The text of this work was the first by the soon - to - be - famous Pietro Trapassi (known as Metastasio), who became a lifelong friend of the singer - Farinelli remarked that the two of them had made their debuts on the same day, and each frequently referred to the other as his caro gemello ("dear twin"). The derivation of Broschi's stage name is not certain, but it was possibly from two rich Neapolitan lawyers, the brothers Farina, who may have sponsored his studies.

Farinelli quickly became famous throughout Italy as il ragazzo ("the boy"). In 1722, he first sang in Rome in Porpora's Eumene and Flavio Anicio Olibrio, as well as taking the female lead in Sofonisba by Luc' Antonio Predieri - it was common practice for young castrati to appear en travesti. All these appearances were greeted with huge public enthusiasm, and an almost legendary story arose that he had to perform an aria with trumpet obbligato, which evolved into a contest between singer and trumpeter. Farinelli surpassed the trumpet player so much in technique and ornamentation that he "was at last silenced only by the acclamations of the audience" (to quote the music historian Charles Burney – this account cannot be verified one way or the other, since no surviving work which Farinelli is known to have performed contains an aria for soprano with trumpet obbligato).

In 1724, Farinelli made his first appearance in Vienna, at the invitation of Pio di Savoia, director of the Imperial Theatre. He spent the following season in Naples. In 1726, he also visited Parma and Milan, where Johann Joachim Quantz heard him and commented: "Farinelli had a penetrating, full, rich, bright and well modulated soprano voice, with a range at that time from the A below middle C to the D two octaves above middle C. ... His intonation was pure, his trill beautiful, his breath control extraordinary and his throat very agile, so that he performed the widest intervals quickly and with the greatest ease and certainty. Passagework and all kinds of melismas were of no difficulty to him. In the invention of free ornamentation in adagio he was very fertile." Quantz is certainly accurate in describing Farinelli as a soprano, since arias in his repertoire contained the highest notes customarily employed by that voice during his lifetime: "Fremano l'onde" in Pietro Torri's opera Nicomede (1728) and "Troverai se a me ti fidi" in Niccolò Conforto's La Pesca (1737) both contain sustained C6. However, the singer also possessed an extraordinarily extensive low range: "Navigante che non spera" in Leonardo Vinci's opera Il Medo (1728) takes him into what might well be described as the alien territory of C3, where a tenor would be more "at home".

Farinelli sang at Bologna in 1727, where he met the famous castrato Antonio Bernacchi, twenty years his senior. In a duet in Orlandini's Antigona, Farinelli showed off all the beauties of his voice and refinements of his style, executing a number of passages of great virtuosity, which were rewarded with tumultuous applause. Undaunted, Bernacchi repeated every trill, roulade, and cadenza of his young rival, but performing all of them even more exquisitely, and adding variations of his own. Farinelli, admitting defeat, entreated Bernacchi to give him instruction in grazie sopraffine ("ultra - refined graces"); Bernacchi agreed.

In 1728, as well as performing in Torri's Nicomede at the Munich court, Farinelli performed another concert before the Emperor in Vienna. In 1729, during the Carnival season in Venice, he sang in two works by Metastasio: as Arbace in Metastasio's Catone in Utica (music by Leonardo Leo) and Mirteo in Semiramide Riconosciuta (music by Porpora). During this period he could really do no wrong - loaded with riches and honours, he was so famous and so formidable as a performer that his rival and friend, the castrato Gioacchino Conti ("Gizziello") is said to have fainted away from sheer despondency on hearing him sing. George Frideric Handel was also keen to engage Farinelli for his company in London, and while in Venice in January 1730, tried unsuccessfully to meet him.

In 1731, Farinelli visited Vienna for a third time. There he was received by the Holy Roman Emperor, Charles VI, on whose advice, according to the singer's first biographer, Giovenale Sacchi, he modified his style, singing more simply and emotionally. After further seasons in Italy, and another visit to Vienna, during which he sang in oratorios in the Imperial chapel, Farinelli came to London in 1734.

In London the previous year, Senesino, a singer who had been a part of Handel's "Second Academy" which performed at the King's Theatre, Haymarket, quarrelled with Handel and established a rival company, Opera of the Nobility, operating from a theatre in Lincoln's Inn Fields. This company had Porpora as composer and Senesino as principal singer, but had not been a success during its first season of 1733 - 34. Farinelli, Porpora's most famous pupil, joined the company and made it financially solvent.

He first appeared in Artaserse, a pasticcio with music by his brother Riccardo and by Johann Adolph Hasse. He sang the memorable arias "Per questo dolce amplesso" (music by Hasse) and "Son qual nave" (music by Broschi), while Senesino sang "Pallido il sole" (music by Hasse). Of "Per questo dolce amplesso", Charles Burney reports: "Senesino had the part of a furious tyrant, and Farinelli that of an unfortunate hero in chains; but in the course of the first air, the captive so softened the heart of the tyrant, that Senesino, forgetting his stage character, ran to Farinelli and embraced him in his own." "Son qual nave", on the other hand, was composed by Riccardo Broschi as a special showpiece for his brother's virtuosic skills. Burney described it thus: "The first note he sung was taken with such delicacy, swelled by minute degrees to such an amazing volume, and afterwards diminished in the same manner to a mere point, that it was applauded for full five minutes. After this he set off with such brilliancy and rapidity of execution, that it was difficult for the violins of those days to keep pace with him."

Both the cognoscenti and the public adored him. The librettist Paolo Rolli, a close friend and supporter of Senesino, commented: "Farinelli has surprised me so much that I feel as though I had hitherto heard only a small part of the human voice, and now have heard it all. He has besides, the most amiable and polite manners ...". Some fans were more unrestrained: one titled lady was so carried away that, from a theatre box, she famously exclaimed: "One God, one Farinelli!" and was immortalised in a detail of Plate II of William Hogarth's "A Rake's Progress" (she may also appear in Plate IV of his series "Marriage à la mode" of 1745).

Though Farinelli's success was enormous, neither the Nobility Opera nor Handel's company was able to sustain the public's interest, which waned rapidly. Though his official salary was £1500 for a season, gifts from admirers probably increased this to something more like £5000, an enormous sum at the time. Farinelli was by no means the only singer to receive such large amounts, which were unsustainable in the long term. As one contemporary observer remarked: "within these two years we have seen even Farinelli sing to an audience of five - and - thirty pounds". Nonetheless, he was still under contract in London in the summer of 1737 when he received a summons, via Sir Thomas Fitzgerald, Secretary of the Spanish Embassy there, to visit the Spanish court.

Apparently intending to make only a brief visit to the Continent, Farinelli called at Paris on his way to Madrid, singing on 9 July at Versailles to King Louis XV, who gave him his portrait set in diamonds, and 500 louis d'or. On 15 July he left for Spain, arriving about a month later. Elisabetta Farnese, the Queen, had come to believe that Farinelli's voice might be able to cure the severe depression of her husband, King Philip V (some contemporary physicians, such as the Queen's doctor Giuseppe Cervi, believed in the efficacy of music therapy). On 25 August 1737, Farinelli was named chamber musician to the king, and criado familiar, or servant to the royal family. He never sang again in public.

Farinelli became a royal favourite and very influential at court. For the remaining nine years of Philip's life, Farinelli gave nightly private concerts to the royal couple. He also sang for other members of the royal family and organised private performances by them, and by professional musicians in the royal palaces. In 1738 he arranged for an entire Italian opera company to visit Madrid, beginning a fashion for opera seria in the Spanish capital. The Coliseo of the royal palace of Buen Retiro was remodelled, and became Madrid's only opera house.

On the accession of Philip's son, Ferdinand VI, Farinelli's influence became even greater. Ferdinand was a keen musician, and his wife, Barbara of Portugal, more or less a musical fanatic (in 1728 she had appointed Domenico Scarlatti as her harpsichord teacher; the musicologist Ralph Kirkpatrick acknowledges Farinelli's correspondence as providing "most of the direct information about Scarlatti that has transmitted itself to our day"). The relationship between singer and monarchs was personally close: he and the queen sang duets together, and the king accompanied them on the harpsichord. Farinelli took charge of all spectacles and court entertainments. He was himself also officially received into the ranks of the nobility, being made a Knight of the Order of Calatrava in 1750, an honour of which he was enormously proud. Although much courted by diplomats, Farinelli seems to have kept out of politics.

In 1759, Ferdinand was succeeded by his half-brother Charles III, who was no lover of music. Charles was the son of Elisabetta Farnese, who had never forgiven Farinelli for his decision to remain at court after Philip V's death, rather than following her into internal exile. It was clear that Farinelli would now have to leave Spain, though he was allowed a generous state pension. He retired to Bologna, where in 1732 he had acquired a property and citizenship. Though rich and still famous, much feted by local notables and visited by such notable figures as Burney, Mozart and Casanova, he was lonely in his old age, having outlived many of his friends and former colleagues. One distinguished friend of his latter years was the music historian, Giovanni Battista (known as "Padre") Martini. He also continued his correspondence with Metastasio, court poet at Vienna, dying a few months after him. In his will, Farinelli asked that he be buried in the mantle of the order of Calatrava, and was interred in the cemetery of the Capuchin monastery of Santa Croce in Bologna. His estate included gifts from royalty, a large collection of paintings including works by Velázquez, Murillo and Jusepe de Ribera, as well as portraits of his royal patrons, and several of himself, one by his friend Jacopo Amigoni. He also had a collection of keyboard instruments in which he took great delight, especially a piano made at Florence in 1730 (called in the will cembalo a martellini), and violins by Stradivarius and Amati.

His original place of burial was destroyed during the Napoleonic wars, and in 1810 Farinelli's great - niece Maria Carlotta Pisani had his remains transferred to the cemetery of La Certosa in Bologna. Farinelli's immediate heir, his nephew Matteo Pisani, sold Farinelli's house in 1798. (It later became the headquarters of a sugar factory, and was demolished in 1949, having been much damaged by bombardment during World War II.) Maria Carlotta bequeathed many of Farinelli's letters to Bologna's University Library and was buried in the same grave as Farinelli in 1850.

Farinelli not only sang, but like most musicians of his time, was a competent harpsichordist. In old age, he learned to play the viola d'amore. He occasionally composed, writing a cantata of farewell to London (entitled Ossequiosissimo ringraziamento, for which he also wrote the text), and a few songs and arias, including one dedicated to Ferdinand VI.

Farinelli lived in Bologna from 1761 until his death. The Farinelli Study Centre (Centro Studi Farinelli) was opened in Bologna in 1998. Major events and achievements include: The restoration of Farinelli's grave in the Certosa of Bologna (2000); An historical exhibition Farinelli a Bologna (2001 and 2005); The inauguration of a City Park in the name of Farinelli, near the site where the singer lived in Bologna (2002); An international symposium Il Farinelli e gli evirati cantori on the occasion of Farinelli's 300th anniversary of his birth (2005); An official publication Il fantasma del Farinelli (2005); The disinterment of Farinelli at the Certosa of Bologna (2006).

A film, Farinelli, directed by Gérard Corbiau, was made about Farinelli's life in 1994. This takes considerable dramatic licence with history, emphasising the importance of Farinelli's brother and reducing Porpora's role, while Handel becomes an antagonist; the singer's time in Spain is ignored almost entirely. Farinelli's supposed sexual exploits are a major element of the film's plot. Though cinematically effective, their basis in reality has not been established.

The film is not the first dramatic work to take Farinelli's life as its source material. He appears as a character in the opera La Part du Diable, composed by Daniel Auber to a libretto by Eugène Scribe, and has the title role in the opera Farinelli by the English composer John Barnett, first performed at Drury Lane in 1839, where his part is, oddly, written for a tenor (this work is itself an adaptation of the anonymous Farinelli, ou le Bouffe du Roi, premiered in Paris in 1835). More recent operas include Matteo d'Amico's Farinelli, la voce perduta (1996) and Farinelli, oder die Macht des Gesanges by Siegfried Matthus (1998).