- 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
According to the Historia Augusta, Firmus (died 273) was an usurper during the reign of Aurelian. The contradictory accounts of his life and the man himself are considered to be a complete fabrication, perhaps based on the later Firmus.
Historia Augusta account
According to Historia Augusta ("Firmus"), Firmus was a man of great wealth. He had his house fitted with square panels of glass, and owned a huge library. His commercial relationships involved Blemmyes, Saracens, and India. He had two elephant tusks, which later Aurelian projected to use as a basis for a statue to Jupiter and which were actually given as a present by Carinus to a lover of his. Physically, Firmus was noteworthy, being huge and very strong. He ate and drank a lot. The importance and threat of Firmus revolt is related to the interruption of the Egyptian grain supply to Rome.
- Jan den Boeft; Jan Willem Drijvers; Daniël den Hengst; Hans Teitler (coauthor) (3 December 2013). Philological and Historical Commentary on Ammianus Marcellinus XXIX. BRILL. p. 150. ISBN 978-90-04-26787-9.
- "Firmus Saturninus Proclus et Bonosus" 3-6, Historia Augusta
- "Aurelianus" xxxii.2‑3, Historia Augusta'
- Zosimus i.61.1
- "Firmus", s.v. "Aurelian", De Imperatoribus Romanis site