The Visigoths were the western tribe of the Goths (a Germanic people) who settled west of the Black Sea sometime in the 3rd century CE. According to the historian Herwig Wolfram, the Roman writer Cassiodorus coined the term Visigothi to mean `Western Goths’ as he understood the term Ostrogothi to mean `Eastern Goths’, sometime in the 6th century CE. Cassiodorus was simply trying to coin a name to differentiate the two tribes of the Gothic people. The designation visigothi seems to have appealed to the Visigoths themselves, however, and they came to apply it to themselves.
When the Huns invaded the area, the Visigoths appealed to the Roman Emperor Valens for sanctuary in the Roman Empire. Valens consented and the Visigoths settled in an area near the Danube. Mistreatment by provincial Roman governors soon led to widespread discontent among the Visigoths and, by 376 CE, open rebellion had broken out. The Visigoths plundered the neighbouring Roman towns, growing in power and wealth as they went.
Emperor Valens took the field with forces mainly drawn from the Eastern Roman Empire and won a number of victories against the Visigoths in what came to be known as The Gothic Wars (376-382 CE). At the Battle of Adrianople in 378 CE the Visigoths won a decisive victory against the forces of Valens (an event which historians mark as the beginning of the end of the Roman Empire) and the emperor himself was killed in the battle.
Theodosius I then became emperor of the Western Roman Empire and tried to halt the progress of the Visigoths as they then swept on to Thrace. In 382 CE a peace treaty was concluded between Athanaric of the Visigoths and Theodosius I of Rome. Theodosius I tried to cement the peace by instituting regional Visigoth governors and, more importantly, trying to unite the Visigoths and the Romans through Christianity. The Visigoths practiced Arian Christianity while Theodosius I, and the Romans, followed the Nicene Creed instituted by Constantine the Great at Nicea in 325 CE. While he was not successful in this, the peace lasted until the death of Theodosius I in 395 CE.
With his death, the Visigoths in service to Rome rejected Roman rule and proclaimed Alaric I their king. Alaric I tried to unite the Visigoths and Romans by having Visigoth governors introduce Roman customs and culture in their regions. While he was moderately successful, Alaric was better suited as a warrior than an administrator and, in 396 CE, led his forces through the Balkans, pillaging as they went, down into Greece. He then turned back to Italy and, after a number of engagements with the faltering Roman forces, sacked Rome in 410 CE.
He died soon after and his successor, Athaulf, led the Visigoths in the conquest of Gaul, establishing the Visigothic Kingdom of Toulouse. Following Athaulf, King Wallia expanded the kingdom and his successor, Euric, enlarged it even further to include a large part of Spain. The Visigoths at this time still practiced Arian Christianity while the inhabitants of Spain were Nicene Christians (recognized today as Catholics). According to some sources, Euric carried out intense persecutions of the Nicene Christians while, according to others, he merely targeted high ranking church officials whom he deemed problematic. After his death, Alaric II became king and, at this time (c. 485 CE) Clovis of the Franks accepted Nicene Christianity and sought to drive the Arian Visigoths from the region.
In 507 CE Alaric II was defeated in battle by Clovis, dying in the engagement, and the Visigothic kingdom became Frankish. The capital was set up at Toledo and a gradual merging of the cultures began between the Romans and the Visigoths. In 711 CE the Muslim forces conquered Spain and, in so doing, accelerated the assimilation of the two cultures into one united front against the conquerors. In time, the native Romans of Hispania and the Visigoths became the united culture of Spain.
In 722 CE, at the Battle of Covadonga, Pelagius of Asturias defeated the Muslim forces and thus began the Christian re-conquest of Spain. In 732 CE, at the Battle of Poitiers (also known as the Battle of Tours) the Frankish King Charles Martel (the Hammer) defeated the Muslim forces under Rahman to permanently halt Muslim incursions into Europe. After driving the Muslims out of Galicia in 739 CE, the Roman Catholic Church was established by the new government as the national faith and official religion of the country. The German Visigoths and the Italian Romans had become the unified people of Spain.