Flavius Richomeres (Richomer) was a Frank who lived in the late 4th century. He took service in the Roman army and made a career as comes, magister militum, and consul. He was married to Ascyla, with whom he had a son Theodemer, who became king of the Franks. He was an uncle of the general Arbogastes.
Around the years 377/378, Richomeres was Comes domesticorum of Emperor Gratian and was transferred from Gaul to Thracia, where he was involved in the Gothic wars of Emperor Valens. At Adrianople he tried to persuade Valens to wait on Gratian for support. When the Gothic leader Fritigern demanded hostages to secure peace from the Romans he volunteered and departed the Roman camp to bring the other hostages safely to Fritigern, but before he arrived some elements of the two armies got out of control and engaged, starting the famous Battle of Adrianople. Richomeres ended up at a battlefield in complete chaos but he saved himself by withdrawing and survived. However the Roman army of Valens was largely destroyed and many officers fell including emperor Valens.
Around 383 he was general in the east (magister militum per orientem) and became consul in 384.
In 388 Theodosius I sent him together with his nephew Arbogastes and Promotus and Timasius against Magnus Maximus, who was defeated.
From the year 388 he served as supreme commander in the Eastern Empire (comes et magister utriusque militiae) until his death in 393. Richomeres was interested in literature and was acquainted with rhetoricians such as Libanius and Augustinus. He introduced the rhetorician Eugenius to his nephew Arbogastes. A few years later Arbogastes seized power in the West Roman Empire. After the death of Valentinian II, Arbogastes promoted Eugenius to be his Emperor, while he himself remained the leader and generalissimo. In 393 Theodosius I organised a campaign against Arbogastes and Richomeres was asked to lead the cavalry against his nephew. On the way from the East to the West he died before the battle took place. Arbogastes lost the battle and committed suicide with his own sword.