In Greek and Roman mythology, Castor ( /ˈkæstər/; Latin: Castōr; Greek: Κάστωρ, Kastōr, "beaver") and Pollux ( /ˈpɒləks/; Latin: Pollūx) or Polydeuces ( /ˌpɒlɨˈdjuːsiːz/; Greek: Πολυδεύκης, Poludeukēs, "much sweet wine") were twin brothers, together known as the Dioscuri ( /daɪˈɒskjəraɪ/; Latin: Dioscūrī; Greek: Διόσκουροι, Dioskouroi, "sons of Zeus"). Their mother was Leda, but Castor was the mortal son of Tyndareus, king of Sparta, and Pollux the divine son of Zeus, who visited Leda in the guise of a swan. Though accounts of their birth are varied, they are sometimes said to have been born from an egg, along with their twin sisters Helen of Troy and Clytemnestra.

In Latin the twins are also known as the Gemini ( /ˈdʒɛmɨnaɪ/; "twins") or Castores ( /ˈkæstəriːz/). When Castor was killed, Pollux asked Zeus to let him share his own immortality with his twin to keep them together, and they were transformed into the constellation Gemini. The pair were regarded as the patrons of sailors, to whom they appeared as St. Elmo's fire, and were also associated with horsemanship.

Jean-Philippe Rameau (French pronunciation: [ʒɑ̃filip ʁaˈmo]; September 25, 1683, Dijon – September 12, 1764) was one of the most important French composers and music theorists of the Baroque era. He replaced Jean-Baptiste Lully as the dominant composer of French opera and is also considered the leading French composer for the harpsichord of his time, alongside François Couperin.

Little is known about Rameau's early years, and it was not until the 1720s that he won fame as a major theorist of music with his Treatise on Harmony (1722). He was almost 50 before he embarked on the operatic career on which his reputation chiefly rests. His debut, Hippolyte et Aricie (1733), caused a great stir and was fiercely attacked for its revolutionary use of harmony by the supporters of Lully's style of music. Nevertheless, Rameau's pre-eminence in the field of French opera was soon acknowledged, and he was later attacked as an "establishment" composer by those who favoured Italian opera during the controversy known as the Querelle des Bouffons in the 1750s. Rameau's music had gone out of fashion by the end of the 18th century, and it was not until the 20th that serious efforts were made to revive it. Today, he enjoys renewed appreciation with performances and recordings of his music ever more frequent.

Nikolaus Harnoncourt (Count Nikolaus de la Fontaine und d'Harnoncourt-Unverzagt) (born 6 December 1929) is an Austrian conductor, particularly known for his historically informed performances of music from the Classical era and earlier. Starting out as a classical cellist, he founded his own period instrument ensemble in the 1950s, and became a pioneer of the Early Music movement. Around 1970, Harnoncourt started to conduct opera and concert performances, soon leading renowned international symphony orchestras, and appearing at leading concert halls, operatic venues and festivals. His repertoire has since widened to include composers of the 19th and 20th century. In 2001 and 2003, he conducted the Vienna New Year's Concert. Harnoncourt is also the author of several books, mostly on questions of performance history and musical aesthetics.

Harnoncourt was born in Berlin, Germany. He was raised in Graz, Austria and studied music in Vienna. His mother, Ladislaja Gräfin von Meran, Freiin von Brandhoven, was the granddaughter of the Habsburg Archduke Johann, the 13th child of the Emperor Leopold II. He is thus descended from various Holy Roman Emperors and other European royalty. His father, Eberhard de la Fontaine Graf d'Harnoncourt-Unverzagt, was an engineer working in Berlin who had two children from a previous marriage. Two years after Nikolaus's birth, his brother Philipp was born. The family eventually moved to Graz, where Eberhard had obtained a post in the state-government (Landesregierung) of Styria.

Véronique Gens (born April 19, 1966, Orléans, France) is a French soprano. She has spent much of her career recording and performing Baroque music.

Gens studied at the Conservatoire de Paris and won first prize of the school. Her debut in 1986 was with William Christie and his Les Arts Florissants. She has since worked with Marc Minkowski, René Jacobs, Christophe Rousset, Philippe Herreweghe, and Jean-Claude Malgoire.

While she started out as a Baroque specialist, Gens has also come into demand for roles in Mozart operas, and as an interpreter of songs by Berlioz, Debussy (see also Beau Soir), Fauré and others. Her numerous recordings include many works by Mozart and Purcell, as well as Joseph Canteloube's Chants d'Auvergne and Berlioz's Nuits d'Été.

Harry Partch (June 24, 1901 – September 3, 1974) was an American composer and instrument creator. He was one of the first twentieth-century composers to work extensively and systematically with microtonal scales, writing much of his music for custom-made instruments that he built himself, tuned in 11-limit (43-tone) just intonation.

Partch was born on June 24, 1901 in Oakland, California soon after his parents, both Presbyterian missionaries, fled the Boxer Rebellion in China. He spent his childhood in small, remote towns in Arizona and New Mexico, where he heard and sang songs in Mandarin, Spanish, and American Indian languages.

As a child, he learned to play the clarinet, harmonium, viola, piano, and guitar. He began to compose at an early age, using the equal-tempered chromatic scale, the tuning system most common in Western music. However, Partch grew frustrated with what he felt were imperfections of the standard system of musical tuning, believing that this system was unsuitable for reflecting the subtle melodic contours of dramatic speech and, as a result, he burned all of his early works.