"Reconquest" of the far west envisaged by emperor Justinian I. Imperial Roman armies took advantage of Visigothic rivalries and established a government at Córdoba. The last Arian Visigothic king, Liuvigild, conquered most of the northern regions (Cantabria) in 574, the Suevic kingdom in 584, and regained part of the southern areas lost to the Byzantines, which King Suintila recovered in 624. Suintila reigned until 631. Only one historical source was written between the years 625 through 711, which comes from Julian of Toledo and only deals with the years 672 and 673. Wamba was the king of the Visigoths from 672 to 680. During his reign, the Visigothic kingdom encompassed all of Hispania and part of southern Gaul known as Septimania. Wamba was succeeded by King Ervig, whose rule lasted until 687. Collins observes that "Ervig proclaimed Egica as his chosen successor" on 14 November 687. In 700, Egica's son Wittiza followed him on the throne according to the Chronica Regum Visigothorum. The kingdom survived until 711, when King Roderic (Rodrigo) was killed while opposing an invasion from the south by the Umayyad Caliphate in the Battle of Guadalete. This marked the beginning of the Umayyad conquest of Hispania, when most of the Iberian Peninsula came under Islamic rule in the early 8th century. A Visigothic nobleman, Pelayo, is credited with beginning the Christian Reconquista of Iberia in 718, when he defeated the Umayyad forces in the Battle of Covadonga and established the Kingdom of Asturias in the northern part of the peninsula. According to Joseph F. O'Callaghan, the remnants of the Hispano-Gothic aristocracy still played an important role in the society of Hispania. At the end of Visigothic rule, the assimilation of Hispano-Romans and Visigoths was occurring at a fast pace. Their nobility had begun to think of themselves as constituting one people, the gens Gothorum or the Hispani. An unknown number of them fled and took refuge in Asturias or Septimania. In Asturias they supported Pelagius's uprising, and joining with the indigenous leaders, formed a new aristocracy. The population of the mountain region consisted of native Astures, Galicians, Cantabri, Basques and other groups unassimilated into Hispano-Gothic society. Other Visigoths who refused to adopt the Muslim faith or live under their rule, fled north to the kingdom of the Franks, and Visigoths played key roles in the empire of Charlemagne a few generations later. In the early years of