The Suebi (also spelled Suevi or Suavi) were a large group of Germanic peoples first reported by Julius Caesar in the 1st century BC. In different contexts over several centuries, peoples within this umbrella category were sometimes simply called the Suebi, although all or most Suebian peoples had their own names as well. They originated near the Elbe River in what is now Eastern Germany. From there, Suebian groups spread across Central Europe, and in the 5th and 6th centuries some took over parts of Spain, Portugal and Italy. Archaeologically, the forerunners of the Suebi before contact with Rome are associated with the Jastorf culture. During the Roman imperial period the Suebi are associated with the so-called "Elbe Germanic peoples" who brought Elbe material culture into new areas to the south and southwest. Linguistically, although contemporary evidence for Roman-era Suebian language is scarce, they spoke a Germanic language, which is believed to be the main predecessor of medieval Old High German, and the modern German language, with all its related dialects.
With the advent of Roman dominance in the 1st and 2nd centuries AD, some Suebi moved into Roman controlled regions near the Neckar river, while a powerful Suebian alliance outside their control maintained a tense relationship with the Roman empire. This was led by the Marcomanni, who settled with other Suebi in remote forests and mountains north of the Roman border along the Danube river, and maintained connections with Suebian and non-Suebian peoples to their north. After their crushing defeat to the Romans in the Marcomannic Wars of the late 2nd century, many Suebi moved into the Roman Empire, or regrouped in areas near the Roman frontier. Notably, the diverse group who came to be known as the Alemanni, took control of Roman territory in what later became medieval Swabia - a cultural region in southern Germany that still bears a version of the Suebian name. During the 3rd and 4th centuries, the Romans were often raided by the Alemanni, Juthungi, Quadi and other Suebi, and attempts to subjugate them had limited success.