Dux Britanniarum in the context of "Scoti"

The Comes Britanniarum (Latin for "Count of the Britains") was a military post in Roman Britain with command over the mobile field army from the mid-4th century onwards. It is listed in the List of Offices as being one of the three commands in Britain, along with the Dux Britanniarum and the Comes litoris Saxonici. His troops were the main field army (comitatenses) in Britain and not the frontier guards (limitanei) commanded by the other two.

Valentinus (fl. mid-4th century, died 369) was a Roman criminal and rebel put down after Count Theodosius's arrival in Britain in AD 369.

Ammianus Marcellinus records that Valentinus was a Pannonian whose brother-in-law Maximinus was close to the emperor Valentinian I. Having committed some serious crime, he was able to have his sentence commuted to exile to Britain, where he resided at the time of the Great Conspiracy. Ammianus does not record that Valentinus took part in that barbarian rising, but does claim that he began planning a new revolt after the arrival of Theodosius. He organized fellow exiles and attempted to bribe local troops to his cause. Discovered, he was given over to Duke Dulcitius for execution, but Ammianus notes that investigation into Valentinus's plot was cursory, lest it produce more unrest in the province.

The Count of the Saxon Shore for Britain (Latin: comes littoris Saxonici per Britanniam) was the head of the Saxon Shore military command of the later Roman Empire.

The post was possibly created during the reign of Constantine I, and was probably in existence by AD 367 when Nectaridus is elliptically referred to as such a leader by Ammianus Marcellinus. The Count's remit covered the southern and eastern coasts of Roman Britain during a period of increasing maritime raids from barbarian tribes outside the empire. The Count was one of three commands covering Britain at the time, along with the northern Dux Britanniarum and central Comes Britanniarum.

Dulcitius may refer to either of two ancient Roman officials active in the fourth century AD.

• Dulcitius (Macedonia) was governor of Macedonia during the reign of the emperor Diocletian. He is chiefly remembered for his role in a hagiographic tale of the persecution of several Christian women in Thessalonica, in 304 AD. As such, he is the eponymous villain of Dulcitius, a 10th-century drama written by Hrotsvitha of Gandersheim.

• Dulcitius (Britannia) was a military leader praised for his abilities by the soldier-historian Ammianus Marcellinus. Although it is not actually stated by Ammianus in his original text, it is often conjectured that Dulcitius was elevated to the position of Dux Britanniarum. If this is the case, he is thought to have been brought to Britain in 369 AD by Count Theodosius in the aftermath of the Great Conspiracy, in which Roman rule on the island faced simultaneous challenge from internal rebellion and external invasion. He might have been appointed Dux as a replacement for Fullofaudes, who is likely to have been killed or lost somewhere in the north of Britain. The Roman rebel Valentinus and his associates were handed over to Dulcitius for execution.