HAVANA (AP).- Revolutionary icon Fidel Castro marked his 85th birthday behind closed doors Saturday as the aging leader famous for railing against Washington increasingly fades from the spotlight even if his outsize persona continues to cast a long shadow over Cuban society and U.S. relations. There were no announcements of how Castro planned to spend the day, though Venezuelan President Hugo Chavez, in Havana for cancer treatment, said via Twitter that he was with his longtime friend and political mentor. “Here with Fidel, celebrating his 85th birthday! Viva Fidel!” Chavez tweeted. The previous night two dozen musical acts from across Latin America held a concert in Castro’s honor. “What we say in the songs of our invited artists will be little next to what he deserves,” Alfredo Vera, one of the organizers, said late Friday.