King John’s Castle at Trim is of at least equal antiquity, and, though in a state of utter ruin, will impress the visitor with a much more correct idea of the ancient feudal stronghold. Trim stands upon the borders of what was once considered the ‘English Pale,’ and lies at an easy distance from Dublin. It is singularly rich in antiquarian remains, and figured largely in the past history of the English rule in Ireland. The castle consists of a triangular walled enclosure, defended by circular flanking towers, and a large and lofty donjon or keep in the centre. The north-east side is 171 yards long, and is defended by four towers, viz. two at the angles, and two intermediate. The west side is 116 yards long, and was defended by flanking towers at the angles, and a gateway tower in the centre. The portcullis groove is very perfect; and it seems, from the projecting masonry, that there had been a drawbridge and barbican to the gate. The third side sweeps round at an easy curve to the Boyne; it is 192 yards long, defended by six flanking towers, including those at the angles and at the gate. The gate tower is circular and is in good preservation, as well as are the arches over the ditch, and the barbican beyond it. The gate had also its portcullis, the groove for which, and the recess for its windlass, are perfect. The entire circuit of the castle wall, then, is 486 yards, defended by ten flanking towers, at nearly equal distances, including those at the gates. The donjon is a rectangular building, the plan of which may be thus described: on the middle of each side of 64 feet rectangles are constructed, the sides perpendicular to the square being 20 feet, and those parallel to it 24 feet: thus a figure of twenty sides is constructed. The thickness of the walls of the large tower is 12 feet, and of the smaller towers from 4 feet 6 inches to 6 feet. The walls were carried up 60 feet above the level of the ground, but on each angle of the large tower, square turrets, 16 feet 6 inches in height, are built. By this arrangement, a large shower of missiles might have been projected in any direction.[129]