Short answers, pulled from the story.
The Goths were a Germanic people who played a major role in the fall of the Western Roman Empire and the emergence of medieval Europe. They were first mentioned by Greco-Roman authors in the 3rd century AD, living north of the Lower Danube in what is now Ukraine, Moldova, and Romania.
The Goths sacked Rome in 410 under their king Alaric I. Although the city's riches were plundered, the civilian inhabitants were treated humanely and only a few buildings were burned, and Alaric died soon afterward.
The Visigoths were the Goths of the west, led by the Balti dynasty and claiming descent from the Thervingi, and they established a Visigothic Kingdom in Spain at Toledo. The Ostrogoths were the Goths of the east, led by the Amali dynasty and claiming descent from the Greuthungi, and under Theodoric the Great they established the Ostrogothic Kingdom in Italy at Ravenna.
According to the 6th-century historian Jordanes, the Goths originated on an island called Scandza and moved to a region called Gothiscandza. Genetic studies of the Wielbark culture Goths found a large majority were autosomally Scandinavian-like, strongly suggesting the culture formed through migration from Southern Scandinavia.
The Battle of Adrianople in 378 was the culmination of the Gothic War of 376-382, in which Goth-led forces inflicted a devastating defeat upon the Romans and killed the Eastern Roman emperor Valens. The conflict began after Gothic refugees who crossed the Danube were mistreated by corrupt officials and driven to rebellion under Fritigern.
The Ostrogothic Kingdom was destroyed by the Eastern Roman Empire in the 6th century, and the Visigothic Kingdom was largely conquered by the Umayyad Caliphate from 711. The Gothic language declined by the mid-500s, though Crimean Gothic was reportedly spoken in Crimea until the 16th century and the Codex Argenteus preserves a partial Bible translation credited to Ulfilas.