In Greek mythology, Enyo ("horror") was an ancient goddess known by the epithet "Waster of Cities" and frequently depicted as being covered in blood and carrying weapons of war. She was frequently portrayed as a companion of Ares, the chief god of war, and has been variously said to be his mother or sister. She was occasionally said to be one of the Graeae.

Enyo's Roman counterpart, Bellona, like Ares's counterpart Mars, was much more popular. She is believed to be one of the numinous gods of the Romans (without a particular mythology and possibly of Etruscan origin), and is supposed by many to have been the Romans' original war deity, predating the identification of Mars with Ares. Her name, Bellona, is derived from the Latin word for "war" (bellum), and is directly related to the modern English word "belligerent" (lit., "war-bearing"). In art, she is portrayed with a helmet, sword, spear, and torch.

Politically, all Senate meetings relating to foreign war were conducted in the Templum Bellonae (Temple of Bellona) on the Collis Capitolinus outside the pomerium. This temple was built in 296 BC and was burned down in 48 BC; Bellona's festival was celebrated on June 3.