Vortigern (in modern Welsh Gwrtheyrn) was a king of the island of Britain from the 5th century AD. If the historical reality of the character is not questioned, it is however advisable to be careful, because what has been transmitted to us about it is more of the legend of the material of Brittany, especially since it is found associated with the Arthurian legend.
We remember the year 410 to locate the end of the Roman presence in the island of Brittany. It was shortly after that Vortigern appears, at this time that English historiography calls the Dark Ages (that is to say, the "dark ages"). He is considered a notable Britto-Roman. According to the sources, he is king of the whole island, around 425, or king of the Brittons-Romans of Kent (the ancient Cantium), around 450.
Etymology
His name is indisputably Brittonic:composed of Uor, great, and Tigern, prince, chief [ref. necessary]. A supposed Roman origin is baseless.
Bede the Venerable in the 8th century mentions him under the name of "Vurtigirnus". The Latinization of his name four centuries later is not enough to make him a Roman of origin, as Ambrosius Aurelianus could be.
According to Geoffrey of Monmouth in his Historia regum Britanniae, he would have become king, after having assassinated King Constantine, and would have allied himself with the Saxons to fight the Picts who came from the north.
This alliance with the Germans gave him a reputation as a traitor in the Celtic world. He would have been deposed by his people in favor of his son Vortimer (in Welsh Gwerthefyr), and would have taken refuge in Wales, where, according to legend, he would have met Merlin the Enchanter. He would then have murdered his son in order to recover the throne.
Vortigern in the Historia regum Britanniae
Accession to the throne
Constant, retired to his convent, left the government of the kingdom to Vortigern, without whom nothing was done. Vortigern then thinks of seizing the royalty. All pretenders to the throne are too young to rule. He therefore begins by seizing the royal treasuries, as well as the fortified cities, on the pretext of foreign threats (the Picts, allied to the Danes and the Norwegians), and places his men there. He brings Picts from Scotland and places them with the king, while treating them lavishly. By stratagem, he gave birth to the Picts the idea that he would be a better king than Constant. Constant is assassinated by the Picts who behead him and offer his head to Vortigern, who feigns pain and has the murderers punished.
The landing of the Saxons
Vortigern becomes king and subjects the lords of the kingdom. But his crime comes to light, and the Picts form a coalition in Albania.
A foreign army, led by the brothers Hengist and Horsa lands in Kent. Vortigern begs them to come and meet him while he is staying in Dorobernia (now Canterbury). Hengist tells him that they are from Saxony in Germania, from which they were expelled according to a custom in the event of overpopulation. The king questions them about their religion, then offers them an alliance:in exchange for their help, he will make their fortune. The Saxons accept and settle in the court of the king. The Picts invade the kingdom and plunder the northern lands, Vortigern and his warriors move towards the enemy for a terrifying battle. The help of the Saxons is decisive, the Picts are defeated and flee.
The matrimonial alliance
In accordance with his promise, the king gives land to Hengist, so that he can reward his warriors. Considering the dangers that threaten the kingdom, the Saxon proposes to bring in other warriors from Germania. The king accepts and grants him the right to build a fortress, Castrum Corrigiae.
Eighteen ships arrive from Germany, full of Saxon warriors. Ronwen, the beautiful daughter of Hengist is on the trip. The Saxon invites the king to his new residence, he instantly falls in love with the young girl. He marries her the following night in exchange for the territory of Kent. This marriage is not to the liking of the other lords, nor of his first three sons, Vortimer, Katigern and Pascent. It was at this time that Saint Germain, Bishop of Auxerre and Saint Loup, Bishop of Troyes, came to the island of Brittany to restore the true faith, bastardized by the impious.
End of reign
Hengist asks Vortigern to bring his son Octa and his cousin Ebissa to defend the lands near Scotland. 300 ships land on the island. The help of this powerful Saxon army allows the king to defeat his enemies. But the Bretons ask Vortigern to get rid of the Saxon allies who terrify the population. Faced with his reluctance, his sovereignty was withdrawn and his son Vortimer was proclaimed king. The latter attacks the Saxons who are masterfully beaten four times and return to Germania.
The new king confiscates and redistributes the property of the Saxons to his people. But he is poisoned by Ronwen, the former queen. He is buried in the city of Trinovantum. Vortigern resumes his royal place and he learns that Hengist, in Germany, is preparing to return to the island with 300,000 soldiers. The fear of a new Saxon invasion and the ruse of Hengist leads to the decision of a meeting at Ambrius. During this conference where we were to talk about peace, Hengist seizes Vortigern and the Saxons cut the throats of 460 Breton lords, they are buried in Kaercaradoc (today Salisbury).
A battle ensued between the two camps, from which the Saxons emerged victorious, not without damage. Vortigern is held hostage, given his life and granted freedom in exchange for occupying the kingdom. Many cities are invested and the inhabitants massacred. The king takes refuge in Cambria.