Sage Stallone during the 'Rocky Balboa' World Premiere; Sylvester Stallone at the 'The Hunger Games' premiere on March 12, 2012 in Los Angeles, California. Credit: Albert L. Ortega/WireImage; Jon Kopaloff/FilmMagic

Sylvester Stallone and his ex-wife Sasha Czack's 36-year-old son, Sage Stallone, was laid to rest on Saturday. 

The family gathered at St. Martin of Tours Catholic Church in Los Angeles to say goodbye, E! News reports.

Sage was found dead in his Los Angeles apartment on July 13. His cause of death remains unknown pending toxicology test results.

"When a parent loses a child there is no greater pain," the 66-year-old Rocky star said in a statement about his son, a filmmaker and actor. "Therefore I am imploring people to respect my talented son's memory and feel compassion for his loving mother Sasha."

He added: "This agonizing loss will be felt for the rest of our lives. "Sage was our first child and the center of our universe and I am humbly begging for all to have my son's memory and soul left in peace."

Sage's mother asked mourners to make a donation to Autism Speaks rather than sending flowers. Czack and Sylvester's youngest son together, Seargeoh, is autistic. Sage is also survived by his half-sister Sistine, Sophia and Scarlet.