Up to 1477, the area under French suzerainty was located west of the Scheldt River and was called "Royal Flanders" (Dutch: Kroon-Vlaanderen, French: Flandre royale). Aside from this the Counts of Flanders from the 11th century onward also held land east of the river as a fief of the Holy Roman Empire, an area called "Imperial Flanders" (Rijks-Vlaanderen or Flandre impériale). Part of the Burgundian Netherlands from 1384, the county was finally removed from French to Imperial control after the Peace of Madrid in 1526 and the Peace of the Ladies in 1529.
Flanders and Flemish (Dutch: Vlaanderen, Vlaams) are likely derived from the Frisian *flāndra and *flāmisk (in Old Frisianflamsk), the roots of which are Germanic *flaumaz meaning "overflow, flooding". The coastal area of Flanders was flooded twice per day from the 3rd century to the 8th century by the North Sea at the time when the coast was frequently visited by Frisian (cattle) traders and probably largely inhabited by Frisians.
The Flemish people are first mentioned in the biography of Saint Eligius (ca. 590–660), the Vita sancti Eligii. This work was written before 684, but only known since 725. This work mentions the "Flanderenses", who lived in "Flandris."