Well placed on rising ground just within the northern gate, it had in former times been a strong fortress, at once overawing Morvaix itself and commanding the approach from the north, the side which was most open to attack. Its outer fortifications formed a long portion of the boundary walls of the city; and in the more desperate times when that district had been constantly overrun by raiders, many a fierce and desperate conflict had raged round its gloomy walls. Gerard saw, not without uneasiness, that the Governor had restored many of the old fortifications, had constructed several more modern works, and had thus greatly strengthened the place. The reason was not far to seek. The Duke ruled by force. He ground the people under the iron heel of military discipline; and so long as he was sure of the strength of his Castle and could maintain his soldiers, the people were powerless. They might protest and murmur and even rise in revolt; but under the frowning menace of the Castle, they were helpless. Every piece of the military machinery was kept in a high state of preparedness for eventualities, and Gerard’s keen soldier’s eye could not fail to note all the evidences of strength and to estimate them at their true value. Whatever the Duke might be, he was a good soldier. Everything about the Castle was regulated with military precision. Stranger though he was, no one attempted to interfere with him or even hinder him as he made his observations. He had been seen to arrive with Gabrielle, and as the Duke had never deemed it possible he would venture inside the fortress and had therefore given no orders concerning him, he was held to be a guest who had been made free of the Castle, and was allowed to go where he would. The knowledge gained in this survey might prove invaluable. The plan of the whole Castle was soon clear in his mind and he detected the one weak spot in the defences against which, should the time come, an attack could best be delivered. This was at a point on the city side of the walls where some works were still in progress. The ground outside rose to within a few feet of the parapet on the top, and gangs of men were at work there: some removing the ground and others deepening the foundations of the walls, while their ladders and tools lay about the place. Gerard smiled with intense satisfaction at the discovery, which might well have vital importance. If a crisis arose which rendered it imperative for him to make a stand against the Governor for a time while awaiting the arrival of his cousin from Cambrai, Dubois could easily collect the men within the Castle and with them make a dash through this breach; or again, if he himself were put under any restraint by the Duke, here was the road of escape. With these thoughts in his mind he made the most careful observation of the exact position of the spot, and then descended from the walls to the courtyards below to find the speediest and most direct road to it.