Jakob Ludwig Felix Mendelssohn Bartholdy, born, and generally known in English-speaking countries, as Felix Mendelssohn (February 3, 1809 – November 4, 1847) was a German composer, pianist, organist and conductor of the early Romantic period.

The grandson of the philosopher Moses Mendelssohn, he was born into a notable Jewish family, although he himself was brought up initially without religion, and later as a Lutheran Christian. He was recognized early as a musical prodigy, but his parents were cautious and did not seek to capitalise on his abilities. Indeed his father was disinclined to allow Felix to follow a musical career until it became clear that he intended seriously to dedicate himself to it. Early success in Germany was followed by travel throughout Europe; Mendelssohn was particularly well received in Britain as a composer, conductor and soloist, and his ten visits there (during which many of his major works were premiered) form an important part of his adult career. His essentially conservative musical tastes however set him apart from many of his more adventurous musical contemporaries such as Liszt, Wagner and Berlioz. The Conservatory he founded at Leipzig became a bastion of this anti-radical outlook. Mendelssohn's work includes symphonies, concerti, oratorios, piano and chamber music. He also had an important role in the revival of interest in the music of Johann Sebastian Bach. After a long period of relative denigration due to changing musical tastes and antisemitism in the late 19th and early 20th centuries, his creative originality is now being recognized and re-evaluated. He is now among the most popular composers of the Romantic era.

Mendelssohn was born in Hamburg, Germany, the son of a banker, Abraham Mendelssohn (who later changed his surname to Mendelssohn Bartholdy, and who was himself the son of the German Jewish philosopher Moses Mendelssohn), and of Lea Salomon, a member of the Itzig family and the sister of Jakob Salomon Bartholdy. He was the family's second child: his older sister Fanny Mendelssohn was also to display, like him, exceptional and precocious musical talent. Felix grew up in an environment of intense intellectual ferment. The greatest minds of Germany were frequent visitors to his family's home in Berlin, including Wilhelm von Humboldt and Alexander von Humboldt. His sister Rebecca married the Belgian mathematician Lejeune Dirichlet. Abraham renounced the Jewish religion; his children were first brought up without religious education, and were baptised as Christians in 1816 (at which time Felix took the additional names Jakob Ludwig – Abraham and his wife were not themselves baptised until 1822.) The name Bartholdy was assumed at the suggestion of Lea's brother, Jakob, who had purchased a property of this name and adopted it as his own surname. Abraham was later to explain this decision in a letter to Felix as a means of showing a decisive break with the traditions of his father Moses: "There can no more be a Christian Mendelssohn than there can be a Jewish Confucius". Felix did not entirely drop the name Mendelssohn as requested but in deference to his father signed his letters and had his visiting cards printed using the form "Mendelssohn Bartholdy".

The family moved to Berlin in 1811. Abraham and Lea Mendelssohn sought to give Felix, his brother Paul, and sisters Fanny and Rebecca, the best education possible. His sister Fanny (later Fanny Hensel), became a well-known pianist and amateur composer; originally Abraham had thought that she, rather than her brother, might be the more musical. However, at that time, it was not considered proper (by either Abraham or Felix) for a woman to have a career in music, so Fanny remained an amateur musician. Six of her early songs were later published (with her consent) under Felix's name. Like Wolfgang Amadeus Mozart before him, Mendelssohn was regarded as a child prodigy. He began taking piano lessons from his mother when he was six, and at seven was tutored by Marie Bigot in Paris. From 1817 he studied composition with Carl Friedrich Zelter in Berlin. This was an important influence on his future career. Zelter had almost certainly been recommended as Felix's teacher by his aunt Sarah Levy, who had been a pupil of W.F. Bach and a patron of C.P.E. Bach and was a talented keyboard player in her own right, often playing with Zelter's orchestra at the Berlin Singakademie (of which she and the Mendelssohn family were leading patrons). Sarah had formed an important collection of Bach family manuscripts which she bequeathed to the Singakademie; Zelter, whose tastes in music were conservative, was also an admirer of the Bach tradition. This undoubtedly played a significant part in forming Felix Mendelssohn's conservative musical tastes. Mendelssohn's own works show his study of Baroque and early classical music. His fugues and chorales especially reflect a tonal clarity and use of counterpoint reminiscent of Johann Sebastian Bach, by whose music he was deeply influenced.

Felix probably made his first public concert appearance at the age of nine, when he participated in a chamber music concert accompanying a horn duo. He was also a prolific composer from an early age. As an adolescent, his works were often performed at home with a private orchestra for the associates of his wealthy parents amongst the intellectual elite of Berlin. Between the ages of 12 and 14, Mendelssohn wrote twelve string symphonies. These works were ignored for over a century, but are now recorded and occasionally played in concerts. He wrote his first published work, a piano quartet, by the time he was thirteen. (It was probably Abraham Mendelssohn who procured the publication of this work by the house of Schlesinger). In 1824, at age 15, he wrote his first symphony for full orchestra (in C minor, Op. 11). At the age of 16 he wrote his String Octet in E-flat major, the first work which showed the full power of his genius. This Octet and his Overture to Shakespeare's A Midsummer Night's Dream, which he wrote a year later, are the best known of his early works. (He wrote incidental music for the play 16 years later in 1842, including the famous Wedding March.) The Overture is perhaps the earliest example of a 'concert overture', (i.e., a piece not written deliberately to accompany a staged performance, but to evoke a literary theme in performance on a concert platform), a genre which was to become a popular form in musical Romanticism.

In 1824 Felix took lessons from the composer and piano virtuoso Ignaz Moscheles who however confessed in his diaries that he had little to teach him. Moscheles became a close colleague and lifelong friend. 1827 saw the premiere — and sole performance in his lifetime — of Mendelssohn's opera, Die Hochzeit des Camacho. The failure of this production left him disinclined to venture into the genre again. Besides music, Mendelssohn's education included art, literature, languages, and philosophy. He was a skilled artist in pencil and watercolour, he could speak (besides his native German) English, Italian, and Latin, and he had an interest in classical literature; Felix translated Terence's Andria for his tutor Heyse in 1825 — Heyse was impressed and had it published in 1826 as a work of 'his pupil, F****' [i.e. 'Felix' (asterisks as provided in original text)]. This translation also qualified Mendelssohn to study at the University of Berlin, where he attended from 1826 to 1829 lectures on aesthetics by Hegel, on history by Eduard Gans and on geography by Carl Ritter.

In 1821 Zelter introduced Mendelssohn to his friend and correspondent, the elderly Goethe, who was greatly impressed by the child, leading to perhaps the earliest confirmed comparison with Mozart in the following conversation with Zelter:

"Musical prodigies […] are probably no longer so rare; but what this little man can do in extemporizing and playing at sight borders the miraculous and I could not have believed it possible at so early an age." "And yet you heard Mozart in his seventh year at Frankfurt?" said Zelter. "Yes", answered Goethe, "[…] but what your pupil already accomplishes, bears the same relation to the Mozart of that time, that the cultivated talk of a grown-up person bears to the prattle of a child"

Felix was invited to meet Goethe on several later occasions and set a number of his poems to music; other of his compositions inspired by Goethe include the overtures Meeresstille und glückliche Fahrt (Calm Sea and a Prosperous Voyage, Op. 27, 1828) and the cantata Die erste Walpurgisnacht (The First Walpurgis Night, Op. 60, 1832).

In 1829, with the backing of Zelter and the assistance of a friend, the actor Eduard Devrient, Mendelssohn arranged and conducted a performance in Berlin of Bach's St Matthew Passion. The orchestra and choir were provided by the Berlin Singakademie. The success of this performance (the first since Bach's death in 1750) was an important element in the revival of Johann Sebastian Bach's music in Germany and, eventually, throughout Europe. It earned Mendelssohn widespread acclaim at the age of twenty. It also led to one of the very few references which Mendelssohn ever made to his origins: 'To think that it took an actor and a Jew's son (Judensohn) to revive the greatest Christian music for the world!' (cited by Devrient in his memoirs of the composer).

On the death of Zelter in 1832, Mendelssohn had some hopes of becoming the conductor of the Berlin Singakademie. However, at a vote in January 1833 he was defeated for the post by the less distinguished Karl Rungenhagen. This may have been because of Mendelssohn's youth, and fear of possible innovations; it was also suspected by some to be on account of his Jewish ancestry. Following this rebuff, Mendelssohn divided most of his professional time over the next few years between England and Düsseldorf, where he was appointed musical director in 1833. In the spring of that year he directed the Lower Rhenish Music Festival, commencing it with a performance of Handel's oratorio Israel in Egypt prepared from the original score which he had found in London. This may be regarded as the start of a Handel revival in Germany begun by Mendelssohn, much as he had reawakened interest in JS Bach. Mendelssohn worked with the dramatist Karl Immermann to improve local theatre standards, and made his first appearance as an opera conductor in Immermann's production of Mozart's Don Giovanni at the end of 1833, when he took umbrage at the audience's protests about the cost of tickets. His frustration at his quotidian duties in Düsseldorf, and its provincialism, led him to resign his position at the end of 1834.

In 1829 Mendelssohn paid his first visit to Britain, where Moscheles, already settled in London, introduced him to influential musical circles. In the summer he visited Edinburgh where he met the composer John Thomson. One of the most significant in terms of his success in Britain was his eighth visit in the Summer of 1844. He conducted five of the Philharmonic concerts in London, and wrote of it

Never before was anything like this season - we never went to bed before half-past one, every hour of every day was filled with engagements three weeks beforehand, and through more music in two months than in all the rest of the year.

On subsequent visits he met Queen Victoria and her musical husband Prince Albert, both of whom were great admirers of his music.

In the course of ten visits to Britain during his life, totalling about 20 months Mendelssohn won a strong following, sufficient for him to make a deep impression on British musical life. Not only did he compose and perform, but he also edited for British publishers the first critical editions of oratorios of Handel and of the organ music of JS Bach. Scotland inspired two of his most famous works, the overture Fingal's Cave (also known as the Hebrides Overture) and the Scottish Symphony (Symphony No. 3). His oratorio Elijah was premiered in Birmingham at the Triennial Music Festival on August 26, 1846. On his last visit to England in 1847 he was the soloist in Beethoven's Piano Concerto no. 4 and conducted his own Scottish Symphony with the Philharmonic Orchestra before the Royal couple. He also worked closely with his protege and friend the English composer William Sterndale Bennett both in London and Leipzig

In 1835, Mendelssohn was appointed as conductor of the Leipzig Gewandhaus Orchestra. This appointment was extremely important for him; he felt himself to be a German and wished to play a leading part in his country's musical life. In its way it was a redress for his disappointment over the Singakademie appointment. Despite efforts by the king of Prussia to lure him to Berlin, Mendelssohn concentrated on developing the musical life of Leipzig, working not only with the orchestra but with the opera house, the Choir of St. Thomas Church, Leipzig and the city’s other choral and musical institutions. Concerts given by Mendelssohn included, apart from many of his own works, three series of ‘historical concerts’ and a number of works by his contemporaries. Mendelssohn was deluged by offers of music from rising composers and would-be composers; amongst these was Richard Wagner who submitted his early Symphony, which (to Wagner’s disgust) Mendelssohn lost or mislaid. Mendelssohn was also able to revive interest in the work of Franz Schubert. Schumann discovered the manuscript of Schubert's Ninth Symphony and sent it to Mendelssohn who promptly premiered it in Leipzig on March 21, 1839, more than a decade after the composer's death. A landmark event during Mendelssohn’s Leipzig years was the premier of his oratorio St. Paul which was given at the Lower Rhine Festival in Düsseldorf in 1836, shortly after the death of the composer’s father, which much affected him. St. Paul seemed to many of Mendelssohn’s contemporaries to be his finest work, and set the seal on his European reputation. The sceptics included Heinrich Heine who wrote of the work’s ‘finest, cleverest calculation, sharp intelligence and, finally, complete lack of naïveté. But is there in art any originality of genius without naïveté?’ — anticipating Wagner and many of Mendelssohn’s later critics who attacked the composer’s supposed glibness.

Friedrich Wilhelm IV came to the Prussian throne in 1840 with ambitions to develop Berlin as a cultural centre. This included the establishment of a music school and reform of music for the church. The obvious choice to head these reforms was Mendelssohn, who was however reluctant to undertake the task, a reluctance perhaps associated with earlier disappointments in the city, especially in the light of his existing strong position in Leipzig. Although Mendelssohn did spend some time in Berlin, writing some church music and also, at the King’s request, music for a production of Sophocles’s Antigone, the funds for the school never materialised and various of the promises (in terms of finance, title and concert programming) made to Mendelssohn by the court were broken. He was therefore not displeased to have the excuse to return to Leipzig.

In 1843, however Mendelssohn did found a major music school, the Leipzig Conservatory, where he persuaded Ignaz Moscheles and Robert Schumann to join him; other prominent musicians, including the string players Ferdinand David and Joseph Joachim, and the music theorist Moritz Hauptmann also became staff members. After Mendelssohn's death in 1847, his conservative tradition was carried on when Moscheles succeeded him as head of the Conservatory.

Mendelssohn was an enthusiastic amateur artist, including drawing, watercolors, and oil painting. His enormous correspondence shows that he could also be a witty writer in German and English — sometimes accompanied by humorous sketches and cartoons in the text.

Although the image was cultivated, especially after his death, of a man always equable, happy and placid in temperament, he was however often given to alarming fits of temper which occasionally led to collapse. On one occasion in the 1830s for example, when his wishes had been crossed "his excitement was increased so fearfully […] that when the family was assembled […] he began to talk incoherently, and in English, to the great terror of them all. The stern voice of his father at last checked the wild torrent of words; they took him to bed, and a profound sleep of twelve hours restored him to his normal state". Such fits may be related to his early death.

Mendelssohn married Cécile Jeanrenaud, the daughter of a French Protestant clergyman, on March 28, 1837. The couple had five children: Carl, Marie, Paul, Lilli and Felix. The youngest child, Felix, contracted measles in 1844 and was left with his health impaired; he died young, in 1851. The eldest, Carl, became a distinguished historian, and professor of history at Heidelberg and Freiburg universities, dying in 1897. Paul Mendelssohn Bartholdy (1841 – 1880) was a noted chemist and pioneered the manufacture of aniline dye. Marie married Victor Benecke and lived in London. Lili married Adolphe Wach, later Professor of Law at Leipzig University. Cécile died less than six years after her husband, on 25 September 1853. In general Mendelssohn's personal life seems to have been fairly conventional compared to his contemporaries Wagner, Berlioz, and Schumann — save as regards his ambiguous relationship with the famed Swedish soprano Jenny Lind, whom he met in October 1844. An affidavit from Lind's husband, Otto Goldschmidt, which is currently held in the archive of the Mendelssohn Scholarship Foundation at the Royal Academy of Music in London, reportedly describes Mendelssohn's 1847 request for Lind (who was then not married) to elope with him to America. The affidavit, though unsealed, is currently unreleased by the Mendelssohn Scholarship Foundation, despite requests to make it public. Mendelssohn met and worked with Lind many times, and wrote the beginnings of an opera, Lorelei, for her, based on the legend of the Lorelei Rhine maidens; the opera was unfinished at his death. He is said to have included a high F-sharp in his oratorio Elijah ("Hear Ye Israel") with Lind's voice in mind, although she did not in fact sing this part until after his death, at a concert in December 1848. In 1847 Mendelssohn attended a London performance of Meyerbeer's Robert le diable — an opera which musically he despised — in order to hear Lind's British debut, in the role of Alice. His friend the critic Chorley, who was with him, wrote "I see as I write the smile with which Mendelssohn, whose enjoyment of Mdlle. Lind's talent was unlimited, turned round and looked at me, as if a load of anxiety had been taken off his mind. His attachment to Mlle. Lind's genius as a singer was unbounded, as was his desire for her success." Mercer-Taylor writes that although there is no currently available hard evidence of a physical affair between the two, "absence of evidence is not evidence of absence." Clive Brown writes that "it has been rumoured that the [affidavit] papers tend to substantiate the notion of an affair between Mendelssohn and Lind, though with what degree of reliability must remain highly questionable." The evidence for such an affair is contested by Cecile and Jens Jorgensen, but also without any hard evidence. Upon Mendelssohn's death Lind wrote, "[He was] the only person who brought fulfillment to my spirit, and almost as soon as I found him I lost him again." In 1869 Lind erected a plaque in Mendelssohn's memory at his birthplace in Hamburg; in 1849 she had set up the Mendelssohn Scholarship Foundation, which makes an award to a British resident young composer every two years in Mendelssohn's memory. The first winner of the scholarship (in 1856), was Arthur Sullivan, then aged 14.

Mendelssohn suffered from bad health in the final years of his life, probably aggravated by nervous problems and overwork. The death of his sister Fanny on May 14, 1847 caused him great distress. Less than six months later, on November 4, Felix himself died in Leipzig after a series of strokes. He was 38. His grandfather Moses, his sister Fanny and both his parents had died from similar apoplexies. His funeral was held at the Paulinerkirche and he is buried in the Trinity Cemetery in Berlin-Kreuzberg.

Throughout his life Mendelssohn was wary of the more radical musical developments undertaken by some of his contemporaries. He was generally on friendly, if somewhat cool, terms with the likes of Hector Berlioz, Franz Liszt, and Giacomo Meyerbeer, but in his letters expresses his frank disapproval of their works. In particular, he seems to have regarded Paris and its music with the greatest of suspicion and an almost Puritanical distaste. Attempts made during his visit there to interest him in Saint-Simonianism ended in embarrassing scenes. He thought the Paris style of opera vulgar, and the works of Meyerbeer insincere. When Ferdinand Hiller suggested in conversation to Felix that he looked rather like Meyerbeer (they were distant cousins, both descendants of Rabbi Moses Isserlis), Mendelssohn was so upset that he immediately went to get a haircut to differentiate himself. It is significant that the only musician with whom he was a close personal friend, Moscheles, was of an older generation and equally conservative in outlook. Moscheles preserved this outlook at the Leipzig Conservatory until his own death in 1870.