Who was the Roman goddess of war?

Bellona was an Ancient Roman goddess of war. Her main attribute is the military helmet worn on her head; she often holds a sword, spear, or shield, and brandishes a torch or whip as she rides into battle in a four-horse chariot. Her iconography was extended further by painters and sculptors following the Renaissance.

Originally named Duellona in the Italic languages, Bellona was an ancient Sabine goddess of war, identified with Nerio, the consort of the war god Mars, and later, with her Greek equivalent Enyo. Her first temple in Rome was dedicated in 296 BCE, where her festival was celebrated on 3rd June.

Her priests were known as Bellonarii and used to wound their own arms or legs as a blood sacrifice to her. These rites took place on 24th March, called the day of blood (dies sanguinis), after the ceremony. In consequence of this practice, which approximated to the rites dedicated to Cybele in Asia Minor, both Enyo and Bellona became identified with her Cappadocian aspect.