Hydatius (c. AD 400 - c. 469) was the bishop of Chaves, Portugal and the author of a chronicle of his own times that provides us with our best evidence for Spanish history in the fifth century.
Hydatius was born around the year 400 in the environs of Lemica, a Roman town near modern Xinzo de Limia in the northwestern Spanish province of Ourense. As a young boy, he travelled as a pilgrim to the Holy Land where he met St. Jerome in the latter's hermitage at Bethlehem. In 428 he was made a bishop, almost certainly of Chaves (the Roman Aquae Flaviae) in the modern Portuguese district of Vila Real, then part of the Roman province of Gallaecia. As bishop he had to come to terms with the presence of non-Roman powers, especially a succession of kings of the Suevi, in a province where imperial control became increasingly nominal during the course of his lifetime. The Suevi had settled in Gallaecia in 411, and there was constant friction between them and the local Hispano-Roman provincials. In this context, Hydatius took part in a deputation of AD 431 requesting assistance in dealing with the Suevi from the general Aetius, the most important representative of the imperial government in the West.
Along with this concern, Hydatius devoted himself to rooting out heresy, not just in his own episcopal diocese, but in the rest of Spain as well. He was in frequent contact with some important bishops of the day, including Thoribius of Astorga and Antoninus of Mérida. Together with Thoribius, he petitioned Pope Leo I (reigned 440-461) for assistance and advice in dealing with heresy. Though Hydatius consistently characterizes Spanish heretics as Manichees, it is generally believed that he meant Priscillianists, followers of the Spanish ascetic and bishop Priscillian, who had been condemned as a heretic by several church councils and executed as a magician by the emperor Magnus Maximus (r. 383-388) around 385. We know very little else about Hydatius' life, though we know he was kidnapped and imprisoned for a time in 460 by local enemies, which suggests he played an important role in the internal politics of Roman Gallaecia.
Hydatius' main claim to historical importance is the chronicle he wrote towards the end of his life. The chronicle was an historical genre very popular in Late Antiquity, though with precedents in older chronographic genres like the consular fasti. A consciously Christian genre, the main goal of the chronicle was to place human history in the context of a linear progression from the Biblical creation to the Second Coming of Christ. Under the entry for each year one or several events were listed, usually with great brevity. The greatest exponent of the form had been the fourth-century bishop Eusebius of Caesarea. Jerome brought the Greek chronicle of Eusebius up to date as far as the year 378, after translating the Eusebian portion into Latin. Jerome's translation and continuation proved very popular, and many others decided to continue Jerome in the same way that he had continued Eusebius.
Hydatius was one such continuator. His continuation begins with a preface explaining his debt to Jerome, and then picks up in the year AD 379. Hydatius had access to a number of chronographic and historical sources - though precisely how many is disputed, and used four parallel chronological systems. Because of this, and particularly towards the end of the chronicle, it can be difficult to translate his chronology into any modern calendar. At the beginning, Hydatius' continuation offers relatively little information for each year, but it becomes increasingly full as the years progress until it resembles an organic literary work more than a typical chronicle. Hydatius' main concern throughout is to show the dissolution of civil society in the western Roman empire and Spain in particular, and he paints a very dark picture of fifth-century life. His deep pessimism may stem from a belief in the imminent end of the world, since he had read the apocryphal letter of Christ to Thomas, which showed that the world would end in May 482. Hydatius may thus have believed that he was chronicling the world's last days, and on occasion he deliberately distorted his account to show events in a gloomier light. This is especially true of the narrative climax of his account, the sack in 456 of the Suevic capital at Braga by the Gothic king Theoderic II, acting in the service of the Roman emperor Avitus (r. 455-456). Regardless of his sometimes very sophisticated literary devices, Hydatius' chronicle is an essential source of information for reconstructing the course of fifth-century events. Moreover, it is our only source for the history of Spain in the period up to 468, at which point the narrative breaks off abruptly. It is assumed that Hydatius never had the opportunity to finish his work and that he must, therefore, have died in that year or soon after.