The Pays d'Aunis stretched from the Marais Poitevin in the north to the Saintonge lowlands and the Niortais in the east and the Rochefortais in the south. In the west, the Aunis bordered the Atlantic. Its main town was La Rochelle .
The Castrum Allionis , a fortress hill near Châtelaillon-Plage , already existed in Gallo-Roman and Merovingian times - this was probably eponymous for the later province via the early medieval name pagus alnensis . This was created in 1374 by a decree of Charles V , who wanted to see the important port city of La Rochelle administered independently. The provincial borders have changed a lot over time; At times, the Île de Ré , the port city of Rochefort or the area around Saint-Jean-d'Angély were also included.
On March 4, 1790, in application of the law of December 22, 1789, the Aunis and parts of the Saintonge formed the new Charente-Inférieure department , which was renamed Charente-Maritime on September 4, 1941 .
The Aunis has always been determined by fishing and agriculture, but ships are likely to have anchored on the shores of the Atlantic even in antiquity. The role of sea trade increased more and more in the late Middle Ages - mainly due to the export of wine to England and other areas of Central and Northern Europe.