Roman usurper in the context of "Pescennius Niger"

Ab urbe condita (Latin: [ab ˈʊrbɛ ˈkɔndɪtaː]; 'from the founding of the City'), or anno urbis conditae (Latin: [ˈannoː ˈʊrbɪs ˈkɔndɪtae̯]; 'in the year since the city's founding'), abbreviated as AUC or AVC, expresses a date in years since 753 BC, the traditional founding of Rome. It is an expression used in antiquity and by classical historians to refer to a given year in Ancient Rome. In reference to the traditional year of the foundation of Rome, the year 1 BC would be written AUC 753, whereas AD 1 would be AUC 754. The foundation of the Roman Empire in 27 BC would be AUC 727. The current year AD 2025 would be AUC 2778.

Usage of the term was more common during the Renaissance, when editors sometimes added AUC to Roman manuscripts they published, giving the false impression that the convention was commonly used in antiquity. In reality, the dominant method of identifying years in Roman times was to name the two consuls who held office that year. In late antiquity, regnal years were also in use, as in Roman Egypt during the Diocletian era after AD 293, and in the Byzantine Empire from AD 537, following a decree by Justinian.

The Crisis of the Third Century, also known as the Military Anarchy or the Imperial Crisis, was a period in Roman history during which the Roman Empire nearly collapsed under the combined pressure of repeated foreign invasions, civil wars and economic disintegration. At the height of the crisis, the Roman state split into three distinct and competing polities. The period is usually dated between the death of Severus Alexander (235) and accession of Diocletian (284).

The crisis began in 235 with the assassination of Emperor Severus Alexander by his own troops. During the following years, the empire saw barbarian invasions and migrations into Roman territory, civil wars, peasant rebellions and political instability, with multiple usurpers competing for power. This led to the debasement of currency and a breakdown in both trade networks and economic productivity, with the Plague of Cyprian contributing to the disorder. Roman armies became more reliant over time on the growing influence of the barbarian mercenaries known as foederati. Roman commanders in the field, although nominally loyal to the state, became increasingly independent of Rome's central authority.

Pacatianus, known in English as Pacatian (/ˈpəkeɪʃ(i)ən/; Latin: Tiberius Claudius Mar[...] Pacatianus; died c. 248) was a usurper in the Danube area of the Roman Empire during the time of Philip the Arab. His praenomen and nomen suggest his ancestors obtained Roman citizenship either during the time of Tiberius or of Claudius.

His life is known from mentions in the histories of Zosimus and Zonaras. However, the chronology of these accounts is obscure, and modern scholars use coinage to establish the timeline of his life and revolt. Zonaras names him as a 'unit commander' of one of the Danube legions, possibly Legio VII Claudia. He was likely a leader in the effort to drive Gothic invaders out of Roman territory in 248, one of the first actions of the Gothic War. Either during this action or soon after he was acclaimed emperor by the Danube legions. Eventually his control extended to the city of Viminacium. According to Zosimus, the news of Pacatian's revolt in Moesia and of Jotapian's near-simultaneous revolt in Syria prompted Philip to make an offer to the Roman Senate to step down. Both Zosimus and Zonoras relate that Philip was advised by the senator Decius, who predicted that Pacatian would soon be killed by his troops. This soon came to pass, and Philip (over Decius' objections) sent Decius to the Danube to find out the causes of the revolt. Decius was promptly acclaimed as emperor by the legions on the Danube, and (though Zonaras records that Decius offered to resign) eventually overcame Philip by the end of 249.

The Battle of Lugdunum, also called the Battle of Lyon, was fought on 19 February 197 at Lugdunum (modern Lyon, France), between the armies of the Roman emperor Septimius Severus and of the Roman usurper Clodius Albinus. Severus' victory finally established him as the sole emperor of the Roman Empire following the Year of the Five Emperors and immediate aftermath.

This battle is said to be the largest, most hard-fought, and bloodiest of all clashes between Roman forces. According to English historian Edward Gibbon, the Roman historian Cassius Dio placed the total number of Roman soldiers engaged for both sides combined at 150,000. Historian Michael Kulikowski states that Severus led the much larger force with the combined legions of Dacia and the Danubian provinces. Historian A. J. Graham supports Gibbon's number of 150,000 soldiers in total, rather than the sometimes cited number of 300,000 in total and therefore 150,000 on each side, which he states to be a commonly accepted mistranslation of Cassius Dio's original language. Graham also analyses the possible forces available to Albinus and states that the numbers on each side could have been roughly equal.

The Historia Augusta (English: Augustan History) is a late Roman collection of biographies, written in Latin, of the Roman emperors, their junior colleagues, designated heirs and usurpers from 117 to 284. Supposedly modeled on the similar work of Suetonius, The Twelve Caesars, it presents itself as a compilation of works by six different authors, collectively known as the Scriptores Historiae Augustae, written during the reigns of Diocletian and Constantine I and addressed to those emperors or other important personages in Ancient Rome. The collection, as extant, comprises thirty biographies, most of which contain the life of a single emperor, but some include a group of two or more, grouped together merely because these emperors were either similar or contemporaneous.

The true authorship of the work, its actual date, its reliability and its purpose have long been matters for controversy by historians and scholars ever since Hermann Dessau, in 1889, rejected both the date and the authorship as stated within the manuscript. Major problems include the nature of the sources that it used, and how much of the content is pure fiction. For instance, the collection contains in all about 150 alleged documents, including 68 letters, 60 speeches and proposals to the people or the senate, and 20 senatorial decrees and acclamations.

Marcus Aurelius Mausaeus Carausius (died 293) was a military commander of the Roman Empire in the 3rd century. He was a Menapian from Belgic Gaul, who usurped power in 286, during the Carausian Revolt, declaring himself emperor in Britain and northern Gaul (Imperium Britanniarum). He did this only 13 years after the Gallic Empire was ended in 273. He held power for seven years, fashioning the name "Emperor of the North" for himself, before being assassinated by his finance minister Allectus.

Allectus (died 296) was a Roman-Britannic usurper-emperor in Britain and northern Gaul from 293 to 296.