World-renowned conductor Seiji Ozawa has died of heart failure at his home in Tokyo, his management office said Friday.

Nathalie Stutzmann gave up a quarter-century career as a contralto to become a conductor.

BOSTON The Boston Symphony Orchestra is asking the music world to help it celebrate former conductor Seiji Ozawa's 85th birthday Tuesday. As part of the celebration, Mayor Marty Walsh has issued a proclamation declaring Tuesday Seiji Ozawa Day in the City of Boston." Ozawa is the longest-serving conductor in Boston Symphony history, holding the title of music director for 29 years from 1973 until 2002. He has also been affiliated with the New Japan Philharmonic, Carnegie Hall, the Vienna Philharmonic, the San Francisco Symphony, the Toronto Symphony Orchestra and New York's Metropolitan Opera. Ozawa announced in 2010 that he had esophageal cancer, but the Boston Symphony said his health currently is stable.