Anachronistic stirrups was used to ensure the safety of the actors , though the crew attempted to conceal or camouflage them for historical authenticity , as they was not then used by the Roman cavalry . Extras playing soldiers attended a boot camp under the guidance of a former Royal Marine . Those actors portraying legionnaires learned to fight by thrusting , not slashing their weapons . Artisans reportedly handmade four thousand costumes using authentic period materials such as cotton , linen , wool and silk , all of which was hand @-@ dyed on set . Pullo was originally written to be a poor horse rider , a reflection that " Romans was notoriously bad horsemen , " according to Heller . However , Stevenson turned out to be " probably the best horseman on the show , " so they rewrite this characteristic because bad horsemanship is difficult to fake .