Daring to the point of extreme rashness where there was a possibility of success, he was prudent and cautious in the extreme when prudence was more necessary than daring.

With absurdly insufficient means he all but conquered Spain for Charles of Austria, and would have succeeded in doing so altogether had he not, from first to last, been thwarted and hampered by jealousy, malignity, stupidity, and irresolution on the part of the king, his courtiers, and the generals who should have been the earl's assistants, but who were his rivals, detractors, and enemies.
It must be owned that Peterborough owed this opposition in some degree to himself.

He was impatient of fools, and took no pains to conceal his contempt and dislike for those whose intellects were inferior to his own.

His independence of spirit and eccentricity of manner set the formal German and Spanish advisers of the king against him, and although adored by the officers and men who served under him, he made almost every man of rank approaching his own who came in contact with him his personal enemy.

Among the bulk of the Spanish people of the provinces in which he warred he was beloved as well as admired, and even to this day legends of the brilliant and indefatigable English general are still current among the people of Catalonia and Valencia.