Gallia Lugdunensis in the context of "Year of the Four Emperors"

Julia Domna (Latin: [ˈjuːli.a ˈdomna]; c. 160 – 217 AD) was Roman empress from 193 to 211 as the wife of Emperor Septimius Severus. She was the first empress of the Severan dynasty. Domna was born in Emesa (present-day Homs) in Roman Syria to an Arab family of priests of the deity Elagabalus. In 187, she married Severus, then-governor of the Roman province of Gallia Lugdunensis. They had two sons, Caracalla and Geta. A civil war over the Roman throne broke out in 193, and shortly afterwards Severus declared himself emperor. The war ended in 197 with the defeat of the last of Severus's opponents.

As empress, Domna was famous for her political, social, and philosophical influence. She received titles such as "Mother of the Invincible Camps". After the elder of her sons, Caracalla, started ruling with his father, she was briefly co-empress with Caracalla's wife, Fulvia Plautilla, until the latter fell into disgrace. Following the death of Severus in 211, Domna became the first empress dowager to receive the title combination "Pia Felix Augusta", which may have implied greater powers being vested in her than what was usual for a Roman empress mother. Her sons jointly inherited the throne, and she acted as mediator in the conflicts that arose between them. Caracalla had Geta killed later that year.

Gaul (Latin: Gallia) was a region of Western Europe first clearly described by the Romans, encompassing present-day France, Belgium, Luxembourg, and parts of Switzerland, the Netherlands, Germany, and Northern Italy. It covered an area of 494,000 km (191,000 sq mi). According to Julius Caesar, who took control of the region on behalf of the Roman Republic, Gaul was divided into three parts: Gallia Celtica, Belgica, and Aquitania. Archaeologically, the Gauls were bearers of the La Tène culture during the 5th to 1st centuries BC. This material culture was found throughout Gaul and as far east as modern-day southern Poland, Slovakia, and Hungary.

Warbands led by the Gaul Brennos sacked Rome in 387 BC, becoming the only time Rome was conquered by a foreign enemy in 800 years. However, Gallia Cisalpina was conquered by the Romans in 204 BC and Gallia Narbonensis in 123 BC. Gaul was invaded after 120 BC by the Cimbri and the Teutons, who were in turn defeated by the Romans by 103 BC. Julius Caesar finally subdued the largest part of Gaul in his campaigns from 58 to 51 BC. Roman control of Gaul lasted for five centuries, until the last Roman rump state, the Domain of Soissons, fell to the Franks in AD 486.

Frankish (reconstructed endonym: *Frankisk), also known as Old Franconian or Old Frankish, was the West Germanic language spoken by the Franks from the 5th to 10th centuries.

Franks under King Chlodio settled in Roman Gaul in the 5th century. One of his successors, named Clovis I, took over the Roman province of Gallia Lugdunensis (in modern day France). Outnumbered by the local populace, the ruling Franks there adapted to its language which was a Proto-Romance dialect. However, many modern French words and place names are still of Frankish origin.

Normandy was a province in the North-West of what later became France under the Ancien Régime which lasted until the later part of the 18th century. Initially populated by Celtic tribes in the West and Belgic tribes in the North East, it was conquered in AD 98 by the Romans and integrated into the province of Gallia Lugdunensis by Augustus. In the 4th century, Gratian divided the province into the civitates that constitute the historical borders. After the fall of Rome in the 5th century, the Franks became the dominant ethnic group in the area and built several monasteries. Towards the end of the 9th century, Viking raids devastated the region, prompting the establishment of the Duchy of Normandy in 911. After 150 years of expansion, the borders of Normandy reached relative stability. These old borders roughly correspond to the present borders of Lower Normandy, Upper Normandy and the Channel Islands. Mainland Normandy was integrated into the Kingdom of France in 1204. The region was badly damaged during the Hundred Years War and the Wars of Religion, the Normans having more converts to Protestantism than other peoples of France. In the 20th century, D-Day, the 1944 Allied invasion of Western Europe, started in Normandy. In 1956, mainland Normandy was separated into two regions, Lower Normandy and Upper Normandy, which were reunified in 2016.

Lugdunum (also spelled Lugudunum, Latin: [ɫʊɡ(ʊ)ˈduːnʊ̃ː]; modern Lyon, France) was an important Roman city in Gaul, established on the current site of Lyon.

The Roman city was founded in 43 BC by Lucius Munatius Plancus, but continued an existing Gallic settlement with a likely population of several thousands. It served as the capital of the Roman province of Gallia Lugdunensis and was an important city in the western half of the Roman Empire for centuries. Two emperors, Claudius and Caracalla, were born in Lugdunum. In the period AD 69–192 , the city's population may have numbered 50,000 to 100,000, and possibly up to 200,000 inhabitants.

Gallia Belgica ("Belgic Gaul") was a province of the Roman Empire located in the north-eastern part of Roman Gaul, in what is today primarily northern France, Belgium, and Luxembourg, along with parts of the Netherlands and Germany.

Before the Roman province came into existence in about 50 BC, the region was conquered by Julius Caesar during his Gallic Wars. His report, the Commentarii de Bello Gallico, described Belgic Gaul as one of the three parts of Gaul (Tres Galliæ), the other two being Gallia Aquitania and Gallia Lugdunensis. Belgica stretched from the Marne and Seine rivers, which Caesar described as a cultural boundary between the Belgae and the Celtic Gauls. In the north and east it stretched all the way to the Rhine. The official Roman province of this name was later created by emperor Augustus in 22 BC, and named after the Belgae, as the largest tribal confederation in the area. However, it also included the territories of the Treveri, Mediomatrici, Leuci, Sequani, and others who Caesar did not explicitly designate as Belgic.

Gallia Aquitania (/ˈɡæliə ˌækwɪˈteɪniə/, Latin: [ˈɡalːi.a akᶣiːˈtaːni.a]), also known as Aquitaine or Aquitaine Gaul, was a province of the Roman Empire. It lies in present-day southwest France and the comarca of Val d'Aran in northeast Spain, 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.