Meanwhile close contact with Roman civilization brought about a gradual conversion of the Goths to Catholicism. One of the most notable early instances of such a conversion was that of the Gothic missionary, Wulfila, who then found it necessary to leave Gothic country for the vicinity of Bulgaria with his congregation, where he translated the Bible into Gothic. Although for a time masters of Italy and Spain, the Goths were defeated by the forces of Justinian I in a final effort to restore the empire. Subsequently they were struck by the Vandals and the Lombards.

Reccared, late 6th century king of Gothic Spain, became Catholic with the remainder of the yet unconverted Goths. Assimilation of the Goths accelerated when the last of them were defeated by the Moors in the early 8th century. The language and culture disappeared except for fragments in other cultures. In the 18th century a small remnant of Ostrogoths may have turned up in the Crimea, but this identification is not certain.

Etymology

The Goths have had many names and have acquired population from many ethnic sources. Peoples under similar names were key elements of the Germanic migrations. Nevertheless they believed, and this belief is supported by the mainstream of scholarship, that the names derived from a single prehistoric ethnonym owned by a uniform culture of south Scandinavia in the mid-first millennium BC, the original "Goths." People of a modern form of that name still live there.

Etymologically the oldest (300 BC) ethnonym for the Goths, "Guton-", Guton- is apparent in Gutones, which appears "in Pytheas cited by Pliny." derives from the same root as that of the Gotlanders ("Gutar"): the Proto-Germanic *Gutaniz. Related, but not the same, is the Scandinavian tribal name Geat, from the Proto-Germanic *Gautoz (plural *Gautaz). Both *Gautoz and *Gutaniz are derived (specifically they are two ablaut grades) from the Proto-Germanic word *geutan, meaning "to pour." The Indo-European root of the pour derivation would be *gheu-d- as it is listed in the American Heritage Dictionary (AHD). *gheu-d- is a centum form. The AHD relies on Julius Pokorny for the same root.

Thus, the Gothic tribes may be designated as "pourers of semen", i.e. "men, people". Another theory connects the people with the name of a river flowing through Västergötland in Sweden, the Göta älv, which drains Lake Vänern into the Kattegat.

Old Norse records do not separate the Goths from the Gutar (Gotlanders) and both are called Gotar in Old West Norse. The Old East Norse term for both Goths and Gotlanders seems to have been Gutar (for instance in the Gutasaga and in the runic inscription of the Rökstone). However the Geats are clearly distinguished from the Goths/Gutar in both Old Norse and Old English literature.