List of Roman legions

The Marian reforms were reforms of the ancient Roman army implemented in 107 BC by the statesman Gaius Marius, for whom they were later named. The reforms originated as a reaction to the military and logistical stagnation of the Roman Republic in the late 2nd century BC. Centuries of military campaigning throughout the Mediterranean and increasing invasions and uprisings across Roman territory had stretched the human and physical resources of the Roman army.

Gaius Marius was a Roman general and statesman. Victor of the Cimbric and Jugurthine wars, he held the office of consul an unprecedented seven times. He was also noted for his important reforms of Roman armies. He set the precedent for the shift from the militia levies of the middle Republic to the professional soldiery of the late Republic; he also improved the pilum, a javelin, and made large-scale changes to the logistical structure of the Roman army.

A proconsul was an official of ancient Rome who acted on behalf of a consul. A proconsul was typically a former consul. The term is also used in recent history for officials with delegated authority.

The Latin word imperator derives from the stem of the verb imperare, meaning 'to order, to command'. It was originally employed as a title roughly equivalent to commander under the Roman Republic. Later it became a part of the titulature of the Roman Emperors as their praenomen. The English word emperor derives from imperator via Old French: Empereür. The Roman emperors themselves generally based their authority on multiple titles and positions, rather than preferring any single title. Nevertheless, imperator was used relatively consistently as an element of a Roman ruler's title throughout the Principate and the Dominate.

Gaius Julius Caesar was a Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey in a civil war, and subsequently became dictator from 49 BC until his assassination in 44 BC. He played a critical role in the events that led to the demise of the Roman Republic and the rise of the Roman Empire.

Gnaeus Pompeius Magnus, known in English as Pompey or Pompey the Great, was a leading Roman general and statesman. He played a significant role in the transformation of Rome from republic to empire. Early in his career, he was a partisan and protégé of the Roman general and dictator Sulla; later, he became the political ally, and finally the enemy, of Julius Caesar.

Marcus Licinius Crassus was a Roman general and statesman who played a key role in the transformation of the Roman Republic into the Roman Empire. He is often called "the richest man in Rome."

Marcus Antonius, commonly known in English as Mark Antony, was a Roman politician and general who played a critical role in the transformation of the Roman Republic from a constitutional republic into the autocratic Roman Empire.

Caesar Augustus, also known as Octavian, was the first Roman emperor; he reigned from 27 BC until his death in AD 14. He is known for being the founder of the Roman Principate, which is the first phase of the Roman Empire, and is considered one of the greatest leaders in human history. The reign of Augustus initiated an imperial cult as well as an era associated with imperial peace, the Pax Romana or Pax Augusta. The Roman world was largely free from large-scale conflict for more than two centuries despite continuous wars of imperial expansion on the empire's frontiers and the year-long civil war known as the "Year of the Four Emperors" over the imperial succession.

Legio II Augusta was a legion of the Imperial Roman army that was founded during the late Roman republic. Its emblems were the Capricornus, Pegasus, and Mars. It may have taken the name "Augusta" from a victory or reorganization that occurred during the reign of Augustus.

Legio III Cyrenaica, was a legion of the Imperial Roman army. The legion had its origins among the forces of Mark Antony during the civil wars of late first century BC. In the Imperial period it was stationed in Egypt, where it played a key role in campaigns against the Nubians and Jews. In the first century AD, it was usually located in Arabia Petraea. There are still records of the legion in Syria at the beginning of the 5th century. The legion symbol is unknown.

Hadrian was Roman emperor from 117 to 138. He was born in Italica, a Roman municipium founded by Italic settlers in Hispania Baetica. He came from a branch of the gens Aelia that originated in the Picenean town of Hadria, the Aeli Hadriani. His father was of senatorial rank and was a first cousin of Emperor Trajan. Hadrian married Trajan's grand-niece Vibia Sabina early in his career before Trajan became emperor and possibly at the behest of Trajan's wife Pompeia Plotina. Plotina and Trajan's close friend and adviser Lucius Licinius Sura were well disposed towards Hadrian. When Trajan died, his widow claimed that he had nominated Hadrian as emperor immediately before his death.

Gallia Aquitania, also known as Aquitaine or Aquitaine Gaul, was a province of the Roman Empire. It lies in present-day southwest France, where it gives its name to the modern region of Aquitaine. It was bordered by the provinces of Gallia Lugdunensis, Gallia Narbonensis, and Hispania Tarraconensis.

Arabia Petraea or Petrea, also known as Rome's Arabian Province or simply Arabia, was a frontier province of the Roman Empire beginning in the 2nd century. It consisted of the former Nabataean Kingdom in Jordan, southern Levant, the Sinai Peninsula and northwestern Arabian Peninsula. Its capital was Petra. It was bordered on the north by Syria, on the west by Judaea and Egypt, and on the south and east by the rest of Arabia, known as Arabia Deserta and Arabia Felix.

Cappadocia is a historical region in Central Anatolia, Turkey. It is largely in the provinces of Nevşehir, Kayseri, Aksaray, Kırşehir, Sivas and Niğde.

Dacia was the land inhabited by the Dacians, its core in Transylvania, stretching to the Danube in the south, the Black Sea in the east, and the Tisza in the west. The Carpathian Mountains were located in the middle of Dacia. It thus roughly corresponds to the present-day countries of Romania, as well as parts of Moldova, Bulgaria, Serbia, Hungary, Slovakia, and Ukraine.

Dalmatia was a Roman province. Its name is derived from the name of an Illyrian tribe called the Dalmatae, which lived in the central area of the eastern coast of the Adriatic Sea. It encompassed the northern part of present-day Albania, much of Croatia, Bosnia and Herzegovina, Montenegro, Kosovo and Serbia, thus covering an area significantly larger than the current Croatian region of Dalmatia. Originally this region was called Illyria or Illyricum.

Galatia was an ancient area in the highlands of central Anatolia, roughly corresponding to the provinces of Ankara and Eskişehir, in modern Turkey. Galatia was named after the Gauls from Thrace, who settled here and became a small transient foreign tribe in the 3rd century BC, following the Gallic invasion of the Balkans in 279 BC. It has been called the "Gallia" of the East.

Germania Inferior was a Roman province from AD 85 until the province was renamed Germania Secunda in the fourth century, on the west bank of the Rhine bordering the North Sea. The capital of the province was Colonia Claudia Ara Agrippinensium.

Germania Superior was an imperial province of the Roman Empire. It comprised an area of today's western Switzerland, the French Jura and Alsace regions, and southwestern Germany. Important cities were Besançon (Vesontio), Strasbourg (Argentoratum), Wiesbaden, and Germania Superior's capital, Mainz (Mogontiacum). It comprised the Middle Rhine, bordering on the Limes Germanicus, and on the Alpine province of Raetia to the south-east. Although it had been occupied militarily since the reign of Augustus, Germania Superior was not made into an official province until c. 85 AD.

Hispania Tarraconensis was one of three Roman provinces in Hispania. It encompassed much of the northern, eastern and central territories of modern Spain along with modern northern Portugal. Southern Spain, the region now called Andalusia was the province of Hispania Baetica. On the Atlantic west lay the province of Lusitania, partially coincident with modern-day Portugal.

Mauretania is the Latin name for a region in the ancient Maghreb. It stretched from central present-day Algeria westwards to the Atlantic, covering northern present-day Morocco, and southward to the Atlas Mountains. Its native inhabitants of Berber ancestry, were known to the Romans as the Mauri and the Masaesyli.

Macedonia was a province of the Roman Empire, encompassing the territory of the former Antigonid Kingdom of Macedonia, which had been conquered by Rome in 168 BC at the conclusion of the Third Macedonian War. The province was created in 146 BC, after the Roman general Quintus Caecilius Metellus defeated Andriscus of Macedon, the last self-styled king of Macedonia in the Fourth Macedonian War. The province incorporated the former kingdom of Macedonia with the addition of Epirus, Thessaly, and parts of Illyria, Paeonia and Thrace.

In modern scholarship, the "late" period of the Roman army begins with the accession of the Emperor Diocletian in AD 284, and ends in 480 with the death of Julius Nepos, being roughly coterminous with the Dominate. During the period 395–476, the army of the Roman Empire's western half progressively disintegrated, while its counterpart in the East, known as the East Roman army remained largely intact in size and structure until the reign of Justinian I.

The Notitia Dignitatum is a document of the late Roman Empire that details the administrative organization of the Western and the Eastern Roman Empire. It is unique as one of very few surviving documents of Roman government, and describes several thousand offices from the imperial court to provincial governments, diplomatic missions, and army units. It is usually considered to be accurate for the Western Roman Empire in the AD 420s and for the Eastern or Byzantine Empire in the AD 390s. However, the text itself is not dated, and omissions complicate ascertaining its date from its content.

Diocletian, nicknamed "Jovius", was Roman emperor from 284 until his abdication in 305. He was born Diocles to a family of low status in the Roman province of Dalmatia. Diocles rose through the ranks of the military early in his career, eventually becoming a cavalry commander for the army of Emperor Carus. After the deaths of Carus and his son Numerian on a campaign in Persia, Diocles was proclaimed emperor by the troops, taking the name Diocletianus. The title was also claimed by Carus's surviving son, Carinus, but Diocletian defeated him in the Battle of the Margus.

The Germanic peoples were historical groups of people that once occupied Central Europe and Scandinavia during antiquity and into the early Middle Ages. Since the 19th century, they have traditionally been defined by the use of ancient and early medieval Germanic languages and are thus equated at least approximately with Germanic-speaking peoples, although different academic disciplines have their own definitions of what makes someone or something "Germanic". The Romans named the area belonging to North-Central Europe in which Germanic peoples lived Germania, stretching East to West between the Vistula and Rhine rivers and north to south from Southern Scandinavia to the upper Danube. In discussions of the Roman period, the Germanic peoples are sometimes referred to as Germani or ancient Germans, although many scholars consider the second term problematic since it suggests identity with present-day Germans. The very concept of "Germanic peoples" has become the subject of controversy among contemporary scholars. Some scholars call for its total abandonment as a modern construct since lumping "Germanic peoples" together implies a common group identity for which there is little evidence. Other scholars have defended the term's continued use and argue that a common Germanic language allows one to speak of "Germanic peoples", regardless of whether these ancient and medieval peoples saw themselves as having a common identity.

The Sasanian Empire, officially known as Eranshahr was the last Iranian empire before the early Muslim conquests of the 7th–8th centuries AD. Named after the House of Sasan, it endured for over four centuries, from 224 to 651 AD, making it the longest-lived Persian imperial dynasty. The Sasanian Empire succeeded the Parthian Empire, and re-established the Persians as a major power in late antiquity alongside its neighbouring arch-rival, the Roman Empire.

Līmes is a modern term used primarily for the Germanic border defence or delimiting system of Ancient Rome marking the borders of the Roman Empire, but it was not used by the Romans for that purpose. The term has been extended to refer to the frontier defences in other parts of the empire, such as in the east and in Africa.

The Scholae Palatinae were an elite military guard unit, usually ascribed to the Roman Emperor Constantine the Great as a replacement for the equites singulares Augusti, the cavalry arm of the Praetorian Guard. The Scholae survived in Roman and later Byzantine service until they disappeared in the late 11th century, during the reign of Alexios I Komnenos.

The Praetorian Guard was an elite unit of the Imperial Roman army that served as personal bodyguards and intelligence agents for the Roman emperors. During the Roman Republic, the Praetorian Guard were an escort for high-rank political officials and were bodyguards for the senior officers of the Roman legions. In 27 BC, after Rome's transition from republic to empire, the first emperor of Rome, Augustus, designated the Praetorians as his personal security escort. For three centuries, the guards of the Roman emperor were also known for their palace intrigues, by which influence upon imperial politics the Praetorians could overthrow an emperor and then proclaim his successor as the new caesar of Rome. In AD 312, Constantine the Great disbanded the cohortes praetoriae and destroyed their barracks at the Castra Praetoria.

Legio I Armeniaca was a pseudocomitatensis legion of the Late Roman Empire. The Legio I Armeniaca was likely creatred in the late 4th century by either Julian the Apostate or Diocletian. It is possible that the name of the legion could mean that it was originally part of the garrison of the Armeniac provinces. This unit, together with its twin legion II Armeniaca, appears to have been included in the imperial field army. It was based in Bezabde until the Persians captured the area in 360. The Legio I Armeniaca took part in Julian's invasion of the Sassanid Empire. The Notitia dignitatum records the legion as being under the command of the magister militum per Orientis around 400.

Magister militum was a top-level military command used in the later Roman Empire, dating from the reign of Constantine the Great. The term referred to the senior military officer of the empire. In Greek sources, the term is translated either as strategos or as stratelates.