The Arena, also known as Naked Warriors, is a 1974 gladiator exploitation film starring Margaret Markov and Pam Grier, and directed by Steve Carver. Joe D'Amato, the film's cinematographer, has stated that he took over direction of the fight scenes in the film.
Pam Grier and Margaret Markov portray female gladiators in ancient Rome, who have been enslaved and must fight for their freedom. This marks the second teaming of Grier and Markov; in 1972 they had starred together in the women in prison film Black Mama, White Mama.
(Summary from Wikipedia)