One of the usual frontier-quarrels between French and Gascons had broken out in 1337 on the borders of Aquitaine. In consequence, Philip VI. of France had, like so many of his predecessors, taken measures to support Edward's Scottish enemies, and given shelter to the exiled boy-king, David Bruce. War between England and France was probably inevitable, but Edward chose to make it a life and death struggle, by laying claim to the throne of France and branding Philip VI. as a usurper. [Sidenote: =The French succession.--The Salic Law.=] The question of the French succession dated from some years back. In 1328 died Edward's uncle, King Charles IV., the last of the direct male descendants of Philip IV. The problem then cropped up for the first time whether the French crown could descend to females, or whether the next male heir must be chosen, although he was but the cousin of the late king. The peers of France adjudged that by the _Salic Law_, an old custom ascribed to the ancient Franks, only male descent counted in tracing claims to the throne. Accordingly they adjudged the kingdom to Philip of Valois, who was crowned as Philip VI. Edward, as own nephew through his mother to Charles IV., had protested at the time; but he had practically withdrawn his protest by doing homage to Philip for the Duchy of Aquitaine, and thereby acknowledging the justice of the award. THE FRENCH SUCCESSION, 1337. PHILIP III., 1270-1285. | +----------+----------------+ | | PHILIP IV., Charles, 1285-1314. Count of Valois. | | +-----------+----+------+------------+ +-----------+ | | | | | LOUIS X., PHILIP V., CHARLES IV., Isabella. PHILIP of Valois, 1314-1316. 1316-1322. 1322-1328. | king 1328-1350. | | | +--+ | | | | | Jane, Edward III. JOHN, Queen of Navarre. 1350-1364. | Charles, King of Navarre.