The Alamanni, Allemanni, or Alemanni were originally an alliance of Germanic tribe
Germanic peoples
The Germanic peoples are an Indo-European ethno-linguistic group of Northern European origin, identified by their use of the Indo-European Germanic languages which diversified out of Proto-Germanic during the Pre-Roman Iron Age.Originating about 1800 BCE from the Corded Ware Culture on the North...

s located around the upper Rhine river (Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

). One of the earliest references to them is the cognomen
The cognomen nōmen "name") was the third name of a citizen of Ancient Rome, under Roman naming conventions. The cognomen started as a nickname, but lost that purpose when it became hereditary. Hereditary cognomina were used to augment the second name in order to identify a particular branch within...

 Alamannicus assumed by Roman Emperor
Roman Emperor
The Roman emperor was the ruler of the Roman State during the imperial period . The Romans had no single term for the office although at any given time, a given title was associated with the emperor...

Caracalla , was Roman emperor from 198 to 217. The eldest son of Septimius Severus, he ruled jointly with his younger brother Geta until he murdered the latter in 211...

, who ruled the Roman Empire
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

 from 211 to 217 and claimed thereby to be their conqueror. The nature of this alliance and their previous tribal affiliations remain uncertain.