The celebrated Austrian conductor Nikolaus Harnoncourt - considered to be the "pope" of the baroque music revival - has died in Vienna aged 86.
A statement on his website said he "took his last breath peacefully surrounded by family".
The Vienna Musikverein, home to the Vienna Philharmonic orchestra, said his death marked the end of an era.
The conductor announced his retirement in a farewell letter in December, citing health reasons.
"My physical capacities mean that I have to cancel all my upcoming projects," he wrote, saying he would not appear on the concert stage again.
He penned the open letter to fans, who found it in the programme for a concert by the ensemble he founded, the Concentus Musicus Wien (CMW).
Thomas Angyan, director of the Vienna Musikverein, said: "I did not think so little time would pass between his retirement and death. We must continue the musical legacy he leaves us."
Harnoncourt's work was considered ground-breaking as he sought to interpret music as faithfully to the original as possible, while his ensemble was at the forefront in its use of period instruments.
He was famed for his concern for historical detail and considered his conducting as alive and romantic, not a relic of history.
Born to a granddaughter of a Habsburg Archduke and an Austrian count, Count Nikolaus de la Fontaine und d'Harnoncourt-Unverzagt was born in Berlin and grew up in Graz, southern Austria.
He studied the cello at Vienna's Academy of Music and joined the Vienna Symphony Orchestra in 1952, where he remained for 17 years.
His intensive research into historical instruments and period performance practice led him to set up the CMW with his wife, Alice, in 1953.
They began giving concerts in 1957 which were credited with reviving Europe's interest in renaissance, baroque and early classical music by the likes of Bach, Beethoven and Haydn.
Harnoncourt began conducting opera and concert performances in the early 1970s and was considered one of the last great post-war Austrian conductors, alongside Herbert von Karajan, Karl Boehm and Carlos Kleiber.
Among his acclaimed recordings were Bach's Brandenburg Concertos (1964) and a pioneering project to record all of Bach's cantatas which was launched in 1971 and completed in 1990.
He went on to become one of the most recorded early-music conductors, although his repertoire later expanded to include 19th and 20th Century composers including Gershwin.
He is survived by his wife and three children.