Short answers, pulled from the story.
Orson Welles declared immediately after finishing the project that The Trial was the best film he had ever made. He began writing the screenplay in 1960 and spent six months rearranging Franz Kafka's original chapters into a new sequence.
Welles started filming in Yugoslavia during 1961 with a budget of 650 million French francs provided by producer Alexander Salkind. Communist restrictions prevented shooting in Prague so the production moved sequences to Dubrovnik Rome Milan and Paris instead.
Anthony Perkins starred as Josef K. while Jeanne Moreau Romy Schneider and Elsa Martinelli played women who became involved in the trial. Welles initially hoped to cast Jackie Gleason as the Advocate but took the role himself when Gleason rejected the part.
Criterion Collection issued a 4K restoration on the 19th of September 2023. A restored version based on the long-lost original 35mm negative appeared on DVD by Milestone Films in 2000.
Welles planned to premiere The Trial at the Venice Film Festival in September 1962 but the film was not completed in time. Festival organizers showed West Side Story instead which won an Academy Award.