The city is the capital of the canton also called Bavay.
The inhabitants of the commune are known as Bavaisiens or Bavaisiennes
The legendary founder and apocryphal history
From the cordelier Jacques de Guise, Jean Wauquelin wrote in his Chronicles of Hainault, a manuscript of the 15th century, that Bavo, a cousin of Priam while fleeing the city of Troy, after many adventures found a hospitable land where he built a city that was called Belges—the current Bavay. According to Wauquelin, seven roads, dedicated to the planets Jupiter, Mars, Venus, Saturn, Mercury, the Sun, and the Moon, left from seven temples in the city. The introduction of an elective monarchy signaled the decline of the city of Belges and the people of the city lost their unity and could not resist the Roman invasions. This episode has been considered a fable by most historians since the 19th century and even more so the bloody infighting which opposed the reign of Belges Queen Ursa by the former King Ursus.
Yet more than 1000 years after the beginning conquests of Rome, Aubert Miraeus and some chroniclers of Hainaut still evoke Bavay as the "Belgian Rome", or Roma Belgica in an apocryphal historiography compiled from other older sources. The columnist and historian of Hainaut, Jacques de Guise who was simply called Belgis (Belge), a name derived by him from Belis (the god Bel).
Various authors and more modern "antiquarians" (people studying antiquity), including Joseph Adolphe Aubenas, while recognizing a lack of evidence in archeology, recalled that other texts, the oldest dating back to at least the 1st century AD also said that the Trojans came to Gaul and founded a great city. Thus, Aubenas, a member of the Society of Antiquaries of France, who in 1804 set up a goal to study the civilization of Gaul, history and French archeology, estimated in 1839 that Jacques de Guise did not invent anything, but only reported what the ancient writers had written before him. Aubenas cites in support of the thesis reported by J de Guise: Ammianus Marcellinus and better Timagenes according to which:
"a part of the population of Gaul (according to the Druids) came from islands far away from beyond the Rhineland, where they had been driven either by frequent wars or by sea inundations".
Rucleri, Hunibaud, and other medieval chroniclers did not invent this story says J Aubenas because Timagene said the same thing after more than 2000 years, and after him, the Trojan origin of the Franks was also affirmed in France:
The birth of Bavay after the conquest was the result of the reorganization of the territory by Augustus (probably between 16BC and 13BC). The parts of Gaul conquered by Caesar were then divided into three provinces. The region between the Seine and the Rhine was Gallia Belgica and its capital was at Reims. It was divided into "cities" (civitates)—administrative districts which were headed by a chief town. Living in this district were some of the fiercest people of Northern Gaul and they occupied a vast area between the Scheldt, the Sambre, and the Meuse: the Nervii.
The town became the capital for the Nervii under the name of Bagacum or Bavacum and, under the Roman Empire, it was an important junction of seven roads, the meeting-place of which was marked by a milestone, destroyed in the 17th century and replaced in the 19th century by a column.
As the centre of the road junction, Bavay was an obligatory passage between Germania and the naval port of Boulogne-sur-Mera bridgehead to Britain. Other routes, seven in total, connected the capital city of the Nervii to the capital cities of neighbouring peoples (Amiens via Arras, Tongeren, Cassel, Trier in the east and Reims in the south). Its position was evidently strategic, but soon these military routes (the future emperor Tiberius transited at Bavay with his armies around 4AD) were used for commercial purposes.
From the Claudian period and especially under the Flavians in the late 1st century the city grew. Large monuments were built: a forum, thermal baths fed by an aqueduct bringing water from a fountain near Floursies located twenty kilometres away, and other buildings with a seemingly official nature adorned the city.
Excavations in the Roman Forum resulted in the discovery of ceramics from the 9th and 10th centuries. The history of the town during this period is unclear and reference is necessary to the larger lines of history of the County of Hainaut. It is likely that the Roman Forum was built as part of a defensive system as some later documents referred to viel castel.
In the 12th century the region of Bavay became part of the County of Hainaut and the city was the capital of a Prévôt.
In the 13th and 14th centuries the city was fortified with a medieval design for the enclosure and its major levee is still visible today.
In 1433 the county of Hainaut of which Bavay was part became part of the prosperous Burgundian Netherlands. In 1519, the Burgundian Netherlands became part of the Holy Roman Empire of Charles V also in a very prosperous period. In 1555 Charles V divided his empire and gave the Netherlands to which Bavay belonged to his son Philip II, King of Spain. Bavay then remained part of the Spanish Netherlands until 1678 when, after numerous battles of conquest by Louis XIV, a large part of the southern Spanish Netherlands was united with the kingdom of France. The confirmation of the unification of Bavay with the kingdom of France came in 1678 with the (Treaty of Nijmegen). Louvignies-Bavay merged with Bavay in 1946.
The city was taken by the Austrians who entered the city on 21 July 1792