So much work was there for the masons that there were not skilled craftsmen enough in the land to do all that was needed. As the years went by and the people gave to the Church of their riches, more new buildings were made and yet more decoration was used. Organs were built and stained glass of lovely hues was put in the windows, orange and blue and red, colours so rich they seemed almost to have caught and held the sunlight. A monk, who was also an artist, wrote "Man's eye knoweth not whereon to gaze; if he look up at the vaults, they are as mantles embroidered with spring flowers; if he regard the walls, there is a manner of paradise; if he consider the light streaming through the windows, he marvelleth at the priceless beauty of the glass and at the variety of this most precious work." So full of riches were these buildings that S. Bernard, and other preachers too, called to the monks to remember their vows of poverty and to return to humbler dwellings like those they had once built where they might worship God. Round the Saxon earthworks, the Normans built strong walls that they might hold them against foreign foe or angry neighbour. By the rivers and on high rocks, they made great keeps or towers, first of timber, later of stone, where they could withdraw if pressed by foes. The stone walls were often 13 feet thick and round about there was a deep moat. The doorway was of stout oak barred with iron. Over this, they would drop the portcullis, a single grate of iron, worked from a chamber above by cords and chains round a windlass. Across the moat, they flung a drawbridge, which could be raised at pleasure. There were only a few rooms in the keep, storerooms below and chambers in the two stories above, for the Norman lord only sought shelter there in times of siege. In such a tower, he was safe enough if he had plenty of food and a well, secure from the enemy. Sometimes the Normans built strong walls and another moat round about the keep, and towers where they kept watch by night and day, looking towards the four quarters of heaven lest an enemy should surprise them. Much later, when the lord brought his family and soldiers to live in the castle, they made it still larger. Storerooms and stables were built round the courtyard and above these were the chambers of the lord and his followers. Here was a fine larder and a kitchen where the ox and wild boar were roasted whole and the mead was brewed and brown bread baked.