He succeeded to his father Euric on 28 December 484. As an Arian, he had persecuted the Catholics of his kingdom, north-west of Gaul bordering with the Frankish kingdom of Clovis. When the latter became catholic, he prepared an expedition against Alaric who under such a threat mitigated his persecution and issued (506) the so called Breviary of Alaric for the subjected Roman populations so as to be reconciled with them. This is a corpus of rules, also known as Lex romana Wisigothorum, excerpted from pre-Justinian Roman sources with an annotated step-by-step interpretatio. After the failed attempt of mediation by Theodoric, the king of the Ostrogoths who was Alaric’s father-in-law and Clovis’ brother-in-law, Alaric met Clovis in battle, was defeated and killed (507) at Vouillé (Campus Vogladensis) near Poitiers. The aftermath of such a defeat was the strong diminution of the Visigoth domain in Gaul, which was partly annexed by Clovis and partly by Theodoric.