Louis I (born c. 1304—died Aug. 25, 1346, near Crécy, Fr.) was the count of Flanders and of Nevers (from 1322) and of Réthel (from 1325), who sided with the French against the English in the opening years of the Hundred Years’ War.
Grandson and heir of Robert of Bethune, count of Flanders, Louis was brought up at the French court and married Margaret of France. His sympathies were entirely French, and he made use of French help in his contests with the Flemish communes.
Under Louis of Nevers, Flanders was practically reduced to the status of a French province. In his time the long contest between Flanders and Holland for the possession of the islands of Zeeland was brought to an end by the Treaty of Paris signed on March 6, 1323, by which the part of Zeeland on the right bank of the Schelde River was assigned to the count of Holland and the rest to the count of Flanders. The latter part of the reign of Louis was remarkable for the successful revolt of the Flemish communes, then rapidly advancing to great material prosperity under Jacob van Artevelde. Artevelde allied himself with Edward III of England in his contest with Philip VI of Valois for the French crown, while Louis espoused the cause of Philip. Louis fell at the Battle of Crécy (1346).