Was the whole cast for the Showtime series "The Tudors" british?

Answer 1

No, no they weren't.

Jonathan Rhys Meyers (King Henry VIII) - Irish
Sam Neill (Cardinal Thomas Wolsey) - Irish
Henry Czerny (Duke of Norfolk) - Canadian
Maria Doyle Kennedy (Queen Katherine of Aragon) - Irish
Nick Dunning (Thomas Boleyn) - Irish
Peter O'Toole (Pope Paul III) - Irish
Alan van Sprang (Sir Francis Bryan) - Canadian
Gerard McSorley (Robert Aske) - Irish
Max von Sydow (Cardinal Otto Truchsess von Waldburg) - Swedish
Lothaire Bluteau (Charles de Marillac) - Canadian
Sarah Bolger (Princess / Lady Mary Tudor) - Irish
Torrance Coombs (Thomas Culpeper) - Canadian
David O'Hara (Henry Howard, Earl of Surrey) - Scottish
James Gilbert (William Brereton) - Canadian