Alamannia or Alemannia was the territory inhabited by the Germanic Alamanni after they broke through the Roman limes in the 3rd century and their name appeared for the first time in 289 in a laudation of emperor Maximian. Up to that point in time the term “Germani” was used for several tribes residing at the Elbe river. About 213 those tribes immigrated into the Main basin area and raided the Romans provinces Southwest Germany, the French Alsace and the eastern part of the Swiss plateau. The Alamanni did not have one Great King, but multiple independent tribal kings.
By 500 Alamannia lost its independence after losing to the Frankish Empire, led by its King Chlodwig, in several battles. Especially the “Battle of Zülpich” was a decisive defeat in 496. The Alamannia tribal duchy was abolished after the so-called “blood court at Cannstatt” in 746 and later, although mostly unrelated to the demise of the Alemanni, the area became a Duchy of Swabia. In the 9th century the term Alemannia was replaced by the old name Swabia. The territory of Alamannia as it existed corresponds roughly to what is today the German region of Baden-Wuerttemberg and Alsace, Bavarian-Swabia, German-speaking Switzerland, Principality of Liechtenstein and Vorarlberg / Austria.
At a later time the term Alamannia was used by the French, Spaniards and others for the population of Germany (e.g. Allemagne = French word for Germany).