sentences:  During 1345, Derby led a whirlwind campaign through Gascony at the head of an Anglo-Gascon army.He smashed two large French armies at the battles of Bergerac and Auberoche, captured more than a hundred French towns and fortifications in Périgord and Agenais and gave the English possessions in Gascony strategic depth.Late in the year he captured the strategically and logistically important town of Aiguillon, "the key to Gascony".