Firmus

For the 4th-century Roman usurper under Valentinian I, see Firmus (4th-century usurper). For the saint and martyr, see Saint Firmus and Saint Rusticus. For the energy company, see Firmus Energy

Firmus (died 273) was a Roman usurper against Aurelian. His story is told by the often unreliable Historia Augusta twice, with the first account the most sketchy and reliable.