The Flemings had sworn allegiance to the crown of France; and they revolted at the idea of perjury, even from an extorted oath.
But to overcome their scruples, Artaveldt proposed to acknowledge the claim of Edward III.

of England to the French crown.

The Flemings readily acceded to this arrangement; quickly overwhelmed Count Louis of Cressy and his French partisans; and then joined, with an army of sixty thousand men, the English monarch, who had landed at Antwerp.

These numerous auxiliaries rendered Edward's army irresistible; and soon afterward the French and English fleets, both of formidable power, but the latter of inferior force, met near Sluys, and engaged in a battle meant to be decisive of the war: victory remained doubtful during an entire day of fighting, until a Flemish squadron, hastening to the aid of the English, fixed the fate of the combat by the utter defeat of the enemy.
A truce between the two kings did not deprive Artaveldt of his well-earned authority.

He was invested with the title of ruward, or conservator of the peace, of Flanders, and governed the whole province with almost sovereign sway.