The search for royal councillors was one of the major difficulties which Henry V had to face once he had achieved the conquest of Normandy. Many local royal officials, having taken the oath of loyalty to the king, were confirmed in their posts; others were brought over from England—a system which proved satisfactory at first. But the finding of personnel for the higher offices presented Henry with a serious problem. Since he was unwilling to trust the native French at so early a stage he could, and did, begin by seeking the counsel of his fellow-countrymen. But this method could not continue indefinitely, since it did not correspond with the intentions lying behind the conquest, planned to be lasting and permanent. However, the alliance with Charles VI, cemented in 1420 by the Treaty of Troyes, meant that the English could now call upon a number of Frenchmen, many of Burgundian origin or sympathy, to serve in the royal council. It was soon realised, too, that the university of Paris was an admirable seed-ground for future royal councillors, especially lawyers, of whom there was need. By the end of Henry V's reign, a number of these graduates were already employed by the English: under the regency of the duke of Bedford they soon achieved a numerical superiority in the royal council in France. From now on, the English dominions were to be ruled by men of these two groups.