Caballe also had a huge impact on the world of pop with the track Barcelona, which she recorded with Freddie Mercury.
Montserrat Caballe, a Spanish opera singer renowned for her bel canto technique and her interpretations of the roles of Rossini, Bellini and Donizetti, has died at the age of 85.
The "Gran Teatre del Liceu" opera house in Barcelona, where Caballe performed more than 200 times, described her as "one of the most important sopranos in history".
Mercury and the Spanish soprano, who starred in 90 opera roles and has been hailed for "inspiring millions" with her voice, first released the anthem in 1987.
After Mercury's death in 1991, the track was featured at the 1992 Summer Olympics and peaked at number 2 in the United Kingdom, the Netherlands and New Zealand.
During her career she was awarded several national and global awards.
She was hospitalised from mid-September because of a vascular problem. She was particularly admired for her purity of voice, vocal shadings and exquisite pianissimos.
In 2015, she was excused from attending a tax fraud trial in Barcelona because of poor health and appeared at a court hearing via video link.
Her success led to her debut that same year at the Metropolitan Opera, as Marguerite in Gounod's Faust.
During her carrer, Montserrat starred in 90 opera roles with almost 4,000 stage performances.
She had two children with Spanish tenor Bernabe Marti who she married in 1964.
Her funeral is reportedly scheduled for Monday.
She was ordered to pay €254,000 (£223,304) and accepted a six-month suspended jail sentence as part of a deal with prosecutors after being accused of funnelling her earnings through a company in Andorra.