Kelly Reilly

Kerra

David Morrissey

General Aulus Plautius

Nikolaj Lie Kaas

Divis

Zoë Wanamaker

Queen Antedia

Stanley Weber

Lindon

Eleanor Worthington-Cox

Cait

Hugo Speer

Lucius

Annabel Scholey

Amena

Julian Rhind-Tutt

Phelan

Ian McDiarmid

King Pellenor

Mackenzie Crook

Veran

Gershwyn Eustache Jnr

Vitus

Barry Ward

Sawyer

Liana Cornell

Ania

Callie Cooke

Islene

Aaron Pierre

Antonius

Joe Armstrong

Gildas

Fortunato Cerlino

Vespasian

Joseph Harmon

Innis

Jodie McNee

Willa

Rhys Yates

Julius

Victoria Hogan

Brieta

Laura Donnelly

Hella

Ben Bradshaw

Elder 5

Robert Ryan

Celtic Slave Master

Billy Jenkins

Young Veran (voice)

Judith Street

Village Lady

Simon Darwen

Guard

Caoilfhionn Dunne

Brearn

Jacobi Jupe

Cyrus

Alice Eloise Ling

Balgae Tribe Child Villager (uncredited)