The Alamanni, Allemanni, or Alemanni were originally an alliance of Germanic tribes located around the upper Rhine river (Germany).

One of the earliest references to them is the cognomen Alamannicus assumed by Roman Emperor Caracalla, who ruled the Roman Empire from 211–217 and claimed thereby to be their conqueror.

The nature of this alliance and their previous tribal affiliations remain uncertain.

Generally its strategy with respect to the Empire was similar to that of the Franks.From the 1st century, the Rhine had become the border between Roman Gaul and tribal Germania.

Germanic peoples, Celts, and tribes of mixed Celto-Germanic ethnicity were settled in the lands along both banks.

The Romans divided these territories into two districts, Germania Inferior and Germania Superior situated along the lower (north) and upper (south) Rhine respectively.Upper Germania included the region between the upper Rhine and the upper Danube, (the Black Forest region that was larger than today: see Hercynian Forest).

The Romans called this the Agri Decumates, (i.e.

"Decumates territories"), a name of unknown origin.

Some scholars have translated the expression as "the ten cantons", but whose cantons of what entity is not known.The exterior Roman fortified border around the area of Germania Superior was called the Limes Germanicus.

The assembled warbands of the Alamanni frequently crossed the limes, attacking Germania Superior and moving into the Agri Decumates.

As a confederation, from the 5th century, they settled the Alsace and expanded into the Swiss Plateau, as well as parts of what are now Bavaria and Austria, reaching the valleys of the Alps by the 8th century.According to Historia Augusta the confederates in the 3rd century were still simply called Germani.

Proculus, an imperial usurper in 280, derived some of his popularity in Gaul by his battle successes against the Alamanni.

The Alamanni thereafter became the nation of Alamannia, that was sometimes independent, but more often was ruled by the Franks.

The name of Germany and the German language, in French, Allemagne, allemand, in Portuguese Alemanha, alemão, in Spanish Alemania, alemán, and in Welsh (Yr) Almaen, almaeneg are derived from the name of this early Germanic nation.

Persian and Arabic also designate Germans Almaani, and Germany as Almaan in Persian and Almaania in Arabic.

In Turkish, German is Alman and Germany is Almanya.