The papal clothes worn by Jude Law in his role as Pope Pius XIII were created by a store which also makes clothing for the real Vatican.
None of the series was filmed in Vatican City. Almost everything - including the Sistine Chapel and the papal library - was reconstructed at Cinecittà Studios in Rome.
The first season had a production budget of $45 million, making it the most expensive Italian television production in history.
The sculpture of Pope John Paul II, which is shown being hit by a meteorite during the opening credits, is a replica of "The Ninth Hour" by Italian artist Maurizio Cattelan. The original sculpture was sold at auction at Christie's for $886,000 in 2001.
Throughout the series, Cardinal Voiello is depicted as a supporter of the Napoli soccer team and a huge fan of star player Gonzalo Higuaín. This detail proved humorous to Italian viewers, as Higuain left Napoli for Juventus a few weeks before the series premiered at the 2016 Venice Film Festival.