- 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 a 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