For more than two decades, the British street artist Banksy has covertly — and often illicitly — stenciled his often politically tinged statements on the walls of structures worldwide, shielded by anonymity.

Now the tables have turned, perhaps, with the opening on Tuesday in Rome of “War Capitalism & Liberty,” a survey of Banksy’s art at the Palazzo Cipolla that its organizers describe as unauthorized by the artist.

“The exhibit symbolizes the fundamental concepts of Banksy’s vision,” said Emmanuele Francesco Maria Emanuele, the chairman of the Fondazione Terzo Pilastro. “Capitalism in crisis; war, which is a consequence; and the notion of freedom that must continue to live inside us independently from the world that surrounds us.”