Following the Hunnic invasion in 370, other Alans, along with other Sarmatians, migrated westward. One of these Alan groups fought together with the Goths in the decisive Battle of Adrianople in 378CE, in which emperor Valens was killed. As the Roman Empire continued to decline, the Alans split into various groups; some fought for the Romans while others joined the Huns, Visigoths or Ostrogoths. A portion of the western Alans joined the Vandals and the Suebi in their invasion of Roman Gaul. Gregory of Tours mentions in his Liber historiae Francorum ("Book of Frankish History") that the Alan king Respendial saved the day for the Vandals in an armed encounter with the Franks at the crossing of the Rhine on December31, 406). According to Gregory, another group of Alans, led by Goar, crossed the Rhine at the same time, but immediately joined the Romans and settled in Gaul.