Trivia

Casals' widow later married condert pianist Eugene Istomin.

First cousin once removed of Luis A. Ferré, former Governor of Puerto Rico (1969-1972).

First cousin once removed of Sor Isolina Ferre, a renowned Puerto Rican humanitarian who was awarded the U.S. Presidential Medal of Freedom by President Bill Clinton in 1999.

First Cousin Twice Removed of Puerto Rican novelist Rosario Ferré.

Godfather of Pablo Eisenberg. Eisenberg, who was named after his godfather, was the son of Casal's longtime friend, cellist Maurice Eisenberg who taught at The Julliard School in New York City during the 1960s and until his death in 1972.