Timasius was a Roman officer, serving under the command of Emperor Valens (r. 364–378), who survived the Battle of Adrianople (378), in which the Roman emperor lost his life. Emperor Theodosius I appointed Timasius magister equitum in 386 and magister peditum in 388. During his tenure as magister militum praesentalis (386–395), Timasius was made a consul, along with Promotus, in 389. In 391, he followed Theodosius in the campaign against the barbarians in Macedonia. In that same year, Theodosius was on the verge of annihilating some barbarian units that were hiding in Roman territory when Timasius told him that the troops needed food and rest; the Roman soldiers, numbed into a slumber by too much food and drink, were taken by surprise and even Theodosius was almost taken prisoner. When Theodosius returned to Constantinople, there was a clash between Timasius and his colleague Promotus and the powerful Rufinus; Theodosius sided with Rufinus, who arranged for Promotus's death.
Timasius also fought in the Battle of the Frigidus of 394, against the usurper Eugenius, as commander-in-chief of the Roman troops, but with the collaboration of Stilicho. After the victory, he returned to the East.
In 395, Theodosius died and his son Arcadius (r. 395–408) had succeeded him on the Eastern throne. The following year, Timasius was the victim of a purge of Theodosius's generals orchestrated by the powerful eunuch Eutropius to get rid of potential opponents. Eutropius specifically forced Bargus, a Syrian sausage-seller brought by Timasius from Sardis and later made tribunus(?) of the East, to falsely accuse Timasius of high treason. As a result, Timasius was put on trial and the judge, Saturninus, exiled him in 396 to the Kharga Oasis of the Libyan Desert. Slightly conflicting accounts report that Timasius was either unable to escape from the oasis or that his attempted escape led him to his death on the border between Egypt and Libya.
- Burns 1994, p. 83.
- Smith 1849, "Timasius, Fl.", p. 1136.
- Martindale, Jones & Morris 1980, p. 1290.
- Matthews 1975, p. 95: "...Fl. Timasius, consul in 389. The name of Timasius' wife, Pentadia, points clearly to a Gallic origin; their son, a young man by 395, was called Syagrius."
- Burns 1994, p. 102.
- Burns 1994, p. 103.
- Burns 1994, p. 105.
- Burns 1994, p. 150.
- Burns 1994, p. 155.
- Bury 1958, "The Supremacy of Stilicho", pp. 117–118; Martindale, Jones & Morris 1980, "Bargus", p. 210.
- Burns 1994, pp. 150, 171; Jackson 2002, p. 165; Bury 1958, "The Supremacy of Stilicho", pp. 117–118.
- Jackson 2002, p. 165.
- Martindale, Jones & Morris 1980, p. 858: "Pentadia, wife of Timasius..."
- Burns, Thomas S. (1994). Barbarians within the Gates of Rome: A Study of Roman Military Policy and the Barbarians, ca. 375–425 A.D. Bloomington, Indiana: Indiana University Press. ISBN 0-253-31288-4.
- Bury, John Bagnell (1958). History of the Later Roman Empire: From the Death of Theodosius I to the Death of Justinian, Volume 2. Mineola, New York: Dover Publications, Inc. ISBN 0-486-20399-9.
- Jackson, Robert B. (2002). At Empire's Edge: Exploring Rome's Egyptian Frontier. New Haven, Connecticut: Yale University Press. ISBN 0-300-08856-6.
- Martindale, John Robert; Jones, Arnold Hugh Martin; Morris, J., eds. (1980). The Prosopography of the Later Roman Empire, Volume II: A.D. 395–527. Cambridge, United Kingdom: Cambridge University Press. ISBN 978-0-521-20159-9.
- Matthews, John Frederick (1975). Western Aristocracies and Imperial Court, A.D. 364-425. Oxford, United Kingdom: Clarendon Press.
- Smith, William (1849). Dictionary of Greek and Roman Biography and Mythology. London, United Kingdom: Taylor, Walton, Maberly.
Magnus Maximus Augustus II (West),
Flavius Theodosius Augustus II (East),
Maternus Cynegius (East)
| Consul of the Roman Empire
with Flavius Promotus
Flavius Valentinianus Iunior Augustus IV,