Cromwell, if we may judge by diaries and records of his day, was the best-informed man in England. He had an undoubted faith in the value of secret service and was ably served by the many agents he employed, not only at home, but also abroad, where their activities helped to lay the broad foundations of that foreign policy which is based upon the principle known as the Balance of Power. It was the Protector's custom to invite to his table men whom he well knew to be what the current vernacular of the time termed "trimmers" and what the American calls a "mugwump"; these men he invariably surprised with the correctness of his information regarding the variety of their political friends and relations, as well as of the dangerous company which they frequented, advising them always in a friendly way to beware. The Protector was one of the few statesmen in Europe who remained a perennial puzzle to Mazarin, during whose large ascendancy on the Continent, Cromwell strengthened the foundations of that naval power which has given England for so long a paramount voice in Europe's councils. His successor Charles II. distinguished himself above all other English monarchs by receiving into his intimate court circle a paid spy of Louis XIV. in the person of Louise de Kérouaille, on whom he conferred the title of Duchess of Portsmouth. This lady, as Duchesse d'Aubigny in France, was at the same time drawing a ducal revenue from the coffers of Louis XIV., while it remains a matter of statistical record that in the year 1681 she took in perquisite from the English Exchequer the sum of £136,000—equal to more than half-a-million sterling of our time. There can be little doubt that the capacity for political intrigue of the Duchess, as well as her complete ascendancy over Charles and her own greed of money, contributed at a later stage to swell the indictment which ultimately led to the banishment of the Stuarts. In her Life of the Duchess, Mrs Colquhoun Grant takes a view generally accepted by historical writers, to wit, that the favourite's character was neither vicious nor depraved, that her conduct was not immoral according to the notions of the age, that she was a woman of immense political capacity, while of a tender and affectionate heart. Her political correspondence, in which she exercised her specific rôle as informer to the French court, was carried on with Madame de Montespan, who is memorable as one of the splendid favourites of Louis. [Illustration: The Duchess of Portsmouth]