Prince Edward had already warned his father of the intentions of the French king, but there was evidently a party at Edward's court that was jealous of his power, and his warnings were slighted. In April 1369, however, war was declared. Edward sent the Earls of Cambridge and Pembroke to his assistance, and Sir Robert Knolles, who now again took service with, him, added much to his strength. The war in Aquitaine was desultory, and, though the English maintained their ground fairly in the field, every day that it was prolonged weakened their hold on the country.