Year 1842 (MDCCCXLII) was a common year starting on Saturday (link will display the full calendar) of the Gregorian Calendar and a common year starting on Thursday of the 12-day slower Julian calendar.

Crazy Horse (Lakota: Tȟašúŋke Witkó (in Standard Lakota Orthography), literally "His-Horse-Is-Crazy" or "His-Horse-Is-Spirited"; ca. 1840 – September 5, 1877) was a Native American war leader of the Oglala Lakota. He took up arms against the U.S. Federal government to fight against encroachments on the territories and way of life of the Lakota people, including leading a war party at the Battle of the Little Bighorn in June 1876.

After surrendering to U.S. troops under General Crook in 1877, Crazy Horse was fatally wounded by a military guard while allegedly resisting imprisonment at Camp Robinson in present-day Nebraska. He ranks among the most notable and iconic of Native American tribal members and has been honored by the U.S. Postal Service with a 13¢ Great Americans series postage stamp.

Sources differ on the precise year of Crazy Horse's birth, but they agree he was born between 1840 and 1845. According to a close friend, he and Crazy Horse "were both born in the same year at the same season of the year", which census records and other interviews place at about 1845.Encouraging Bear, an Oglala medicine man and spiritual adviser to the Oglala war leader, reported that Crazy Horse was born "in the year in which the band to which he belonged, the Oglala, stole One Hundred Horses, and in the fall of the year", a reference to the annual Lakota calendar or winter count. Among the Oglala winter counts, the stealing of 100 horses is noted by Cloud Shield, and possibly by American Horse and Red Horse owner, as equivalent to the year 1840-41. Oral history accounts from relatives on the Cheyenne River Reservation place his birth in the spring of 1840. On the evening of his son's death, the elder Crazy Horse told Lieutenant H. R. Lemly that his son "would soon have been thirty-seven, having been born on the South Cheyenne river in the fall of 1840".

Eli Parish (28 February 1808, Teignmouth, Devonshire, England – 25 January 1849, Vienna) was an English harpist and composer. He changed his name to Elias Parish Alvars, and sometimes used the pseudonym Albert Alvars in his publications.

The baptismal record found at St James’s Church, West Teignmouth, reports: "Eli, son of Joseph and Mary Ann Parish". His father, an organist, voice teacher and book dealer in Teignmouth, gave him his first musical instruction.

Eli gave his first concert in Totnes in 1818. In 1820 he was sent to London to study with Nicolas Bochsa. In 1822 he applied to the Royal Academy of Music, where Bochsa had been appointed harp professor. However, he was not accepted as a student there, probably because of his family’s inability to pay the tuition. (Joseph Parish had to declare bankruptcy in 1818.) In any case, Eli Parish continued his lessons with Bochsa thanks to the help of a local landowner.

After the Dresden concert, Hector Berlioz wrote: "In Dresden, I met the prodigious English harpist Elias Parish Alvars, a name not yet as renowned as it ought to be. He had just come from Vienna. This man is the Liszt of the harp. You cannot conceive all the delicate and powerful effects, the novel touches and unprecedented sonorities, that he manages to produce from an instruments in many respects so limited. His fantasy on Moses (imitated and adapted for the piano with such happy results by Thalberg), his Variations for harmonic notes on the Naiads Chorus from Oberon, and a score of similar taste, delighted me more than I can say…" (Mémoires de Hector Berlioz, Paris, 1903);

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

The grandson of the philosopher Moses Mendelssohn, Felix Mendelssohn was born into a prominent Jewish family, although initially he was raised without religion and was later baptised as a Lutheran Christian. Mendelssohn was recognised early as a musical prodigy, but his parents were cautious and did not seek to capitalise on his talent.

Early success in Germany, where he also revived interest in the music of Johann Sebastian Bach, 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 Franz Liszt, Richard Wagner and Hector Berlioz. The Leipzig Conservatoire (now the University of Music and Theatre Leipzig), which he founded, became a bastion of this anti-radical outlook.

Louise Farrenc (31 May 1804 – 15 September 1875) was a French composer, virtuosa pianist and teacher. Born Jeanne-Louise Dumont in Paris, she was the daughter of Jacques-Edme Dumont, a successful sculptor, and sister to Auguste Dumont.

Louise Farrenc enjoyed a considerable reputation during her own lifetime, as a composer, a performer and a teacher. She began piano studies at an early age with a Senora Soria, a former student of Muzio Clementi, but when it became clear she had the talent of a professional pianist, she was also given lessons by such masters as Ignaz Moscheles and Johann Nepomuk Hummel. Because she also showed great promise as a composer, her parents decided to let her study composition with Anton Reicha, at the time composition teacher at the Conservatoire. it is not yet clear if Louise Farrenc followed his classes there, as the composition class was at the time one of the classes opened only to men. She met Aristide Farrenc, a flute student ten years her senior, who performed at some of the concerts regularly given at the artists' colony of the Sorbonne, where Louise's family lived. She married him in 1821. She then interrupted her studies to concertize throughout France with her husband. He soon grew tired of the concert life and decided to open a publishing house in Paris, which as Éditions Farrenc, was one of France’s leading music publishers for nearly 40 years.