talks, which led to a peace treaty. In 506, the Visigoths captured the city of Dertosa in the Ebro valley. There they captured the Roman usurper Peter and had him executed. Battle of Vouillé and aftermath After a few years, however, Clovis violated the peace treaty negotiated in 502. Despite the diplomatic intervention of Theodoric, king of the Ostrogoths and father-in-law of Alaric, Clovis led his followers into Visigothic territory. Alaric was forced by his magnates to meet Clovis in the Battle of Vouillé (summer 507) near Poitiers; there the Goths were defeated and Alaric slain, according to Gregory of Tours, by Clovis himself. The most serious consequence of this battle was not the loss of their possessions in Gaul to the Franks; with Ostrogothic help, much of the Gallic territory was recovered, Herwig Wolfram notes, perhaps as far as Toulouse. Nor was it the loss of the royal treasury at Toulouse, which Gregory of Tours writes Clovis took into his possession. As Peter Heather notes, the Visigothic kingdom was thrown into disarray "by the death of its king in battle." Alaric's heirs were his eldest son, the illegitimate Gesalec, and his younger son, the legitimate Amalaric who was still a child. Gesalec proved incompetent, and in 511 King Theodoric assumed the throne of the kingdom ostensibly on behalf of Amalaric—Heather uses the word "hijacked" to describe his action. Although Amalaric eventually became king in his own right, the political continuity of the Visigothic kingdom was broken; "Amalaric's succession was the result of new power structures, not old ones," as Heather describes it. With Amalaric's death in 531, the Visigothic kingdom entered an extended period of unrest which lasted until Leovigild assumed the throne in 568. Ability as king In religion Alaric was an Arian, like all the early Visigothic nobles, but he greatly mitigated the persecution policy of his father Euric toward the Catholics and authorized them to hold in 506 the council of Agde. He was on uneasy terms with the Catholic bishops of Arelate (modern Arles) as epitomized in the career of the Gallo-Roman Caesarius, bishop of Arles, who was appointed bishop in 503. Caesarius was suspected of conspiring with the Burgundians, whose king had married the sister of Clovis, to assist the Burgundians capture Arles. Alaric exiled him for a year to Bordeaux in Aquitania, then allowed him to return unharmed when the crisis had passed.