Starz has cast the role of Gannicus, the gladaiator before Spartacus (and presumably before Crixus became the Champion of Capua). The Hollywood Reporter had the following news:

Starz casts 'Spartacus' prequel, firms up story line
Dustin Starz is firming up the cast and story line for its "Spartacus" prequel series, whose subtitle will be the epic-sounding "Gods of the Arena."

Three Australian actors have joined the cast, including Dustin Clare in the lead role.

Clare ("Underbelly," "Satisfaction") will play Gannicus, the champion gladiator in the House of Batiatus before Spartacus came along.

"Spartacus" star Andy Whitfield, who was sidelined for several months after being diagnosed with cancer, will make a brief appearance in the prequel. He has been cleared by doctors to return to work.

"Spartacus: Gods of the Arena" will begin production on six episodes next month and will hit the air in January. Season 2 of "Spartacus: Blood and Sand," starring Whitfield, will begin production immediately after "Arena" wraps and air later in 2011 for an undetermined number of episodes.

Starz also has cast Jaime Murray ("Dexter) as a Capua social climber and Marisa Ramirez ("General Hospital") as a slave girl.

In the prequel, Batiatus (John Hannah) is not yet the head of his family or of the gladiator training school. Gannicus is the lead gladiator in the Ludus, but the House of Batiatus hasn't earned social respect or the right for its gladiators to fight in championship bouts. Gannicus struggles to turn around the House's luck.

Source