Kevin McKidd Lucius Vorenus Actor Ray Stevenson Titus Pullo Actor Ciarán Hinds Gaius Julius Caesar Actor Kenneth Cranham Pompey Magnus Actor Polly Walker Atia of the Juli Actor James Purefoy Mark Antony Actor Tobias Menzies Marcus Junius Brutus Actor Lindsay Duncan Servilia of the Junii Actor Indira Varma Niobe Actor Max Pirkis Gaius Octavian Actor Kerry Condon Octavia of the Julii Actor Karl Johnson Porcius Cato Guest Star David Bamber Marcus Tullius Cicero Guest Star Nicholas Woodeson Posca Guest Star Coral Amiga Vorena the Elder Guest Star Suzanne Bertish Eleni Guest Star Chiara Mastalli Eirene Guest Star Manfredi Aliquo Castor Guest Star Lidia Biondi Merula Guest Star Ian McNeice Newsreader Guest Star Bruno Heller Executive Producer William J. Macdonald Executive Producer John Milius Executive Producer Anne Thomopoulos Executive Producer Frank Doelger Executive Producer Lucy Richer Executive Producer