Eleonore Schoenfeld, internationally renowned cellist and longtime USC Thornton School of Music professor, died Jan. 1 of a heart attack at her home in La Canada Flintridge, Calif. She was 81.

Schoenfeld had been on the faculty of the USC Thornton School since 1959. At the time of her death, she was still actively teaching and serving as the chair of the school’s strings department and as the Gregor Piatigorsky Professor of Violoncello.

She and sister Alice Schoenfeld lived, worked and played music together since childhood, performing as a violin-cello twosome known as the Schoenfeld Duo. The two performed around the world for many years and were both professors in the USC Thornton School.

Born in Maribor, Slovenia, Schoenfeld moved to Berlin at age six and began as a ballet dancer with the Berlin State Opera. She switched to cello at age 11 and earned her artist diploma at the famed Hochschule für Musik in Berlin. She and her sister performed around Europe as child prodigies, and they had made a name for themselves by the time their family immigrated to Los Angeles in 1952.

Throughout her career, Schoenfeld made more than 200 recordings of solo and chamber music, including works especially written for the Schoenfeld Duo, for top television and radio stations in Europe and the United States. She was a regular guest artist at national and international festivals and conducted many master classes and seminars during her international tours.

In addition to her full-time teaching position at USC, Schoenfeld was a master teacher at the Colburn School of Performing Arts in Los Angeles, and she worked on the faculty of the Arts Academy in Idyllwild, Calif.

Since 1979, Schoenfeld had directed the International Gregor Piatigorsky Seminar for Cellists, organized by USC every other year. She was the seminar’s artist-in-residence in 1980, 1989 and 2005.

Schoenfeld received many awards for her musical achievements, including the prestigious Ramo Music Faculty Award from USC in 1990, the Eva Janzer Memorial Award Grande Dame du Violoncelle from the University of Indiana in 1993 and the National Distinguished Service Award from the American String Teachers’ Association in 1996.

She is survived by her sister Alice.