Schoenberg’s son, Larry, 83, said the sheet music was stored in a building behind his home. Both buildings were destroyed in fires last week.
Other Schoenberg memorabilia was also destroyed, including photographs, letters and posters.
“For a company that focused exclusively on Schoenberg’s works, this loss represents not only the physical destruction of property, but also a profound cultural blow,” Larry said in a statement.
He called the collection “a must-have” for musicians who rely on “carefully selected editions” of his father’s back catalogue.
Arnold Schoenberg was born into a Jewish family in Vienna in 1874. He achieved great success as a composer in Berlin before fleeing to the United States in 1933 to escape persecution by the Nazis.
He eventually settled in Los Angeles, where he continued his groundbreaking compositions. He was known for atonality and his 12-tone technique, which departed from conventional harmony. He died in 1951 at the age of 76 in Los Angeles.
In a statement, Belmont said it hopes to create digital copies of the score.
“We hope that in the near future we will be able to ‘rise from the ashes’ in a fully digital form,” the statement said.
Most of Schoenberg’s original manuscripts are kept in a museum in Vienna, Austria.
Firefighters are still struggling to control the massive wildfires in Los Angeles that began in early January. So far, they have killed at least 24 people, destroyed thousands of buildings and forced tens of thousands of people to flee their homes.
Two large fires are still raging in Los Angeles, including the largest fire in the Palisades, which has burned more than 24,000 acres.
