The next period in the history of Babylonian brick-making is that belonging to the times of the second dynasty of Lagash and the first dynasty of Ur (i.e. _circ._ 2450 B.C.). The type of brick characteristic of this age resembles that of the preceding in regard to shape but not in regard to size. The bricks of Ur-Engur, king of Ur, and of Gudea, the most renowned ruler of the second dynasty of Lagash (_circ._ 2450 B.C.) are square like those of their Semitic predecessors, Shar-Gâni-sharri and Narâm-Sin, but very much smaller, measuring a little over 12 x 12 inches, and this small square brick remained in use, with occasional slight variations, till the close of Mesopotamian history. The transition from the large brick used by the kings of Agade to the small brick in question was doubtless effected only gradually, for the bricks of Ur-bau, ruler of Lagash some time before Gudea, are larger than those of the latter king, but after the time of Gudea and Ur-Engur, the shape and size of the bricks became more or less stereotyped. The bricks of Ur-Engur himself vary somewhat from those of Gudea, thus the solid mass underlying the temple-tower at Nippur, which was constructed by Ur-Engur, is composed of bricks measuring only 9 × 6 × 3 inches, the arms of the causeway on the other hand are built of larger bricks measuring 14 × 14 × 6 inches. Kiln-burnt bricks were always used for the important parts of the building in Babylonia, the crude sun-dried bricks which as a rule formed the core of the terraced platforms, being revetted with a wall of burnt brick, or sometimes, in the case of Assyria with a supporting wall of stone. The reason of course for this lay in the inability of sun-dried bricks to resist damp, and their corresponding tendency to disintegrate. The bricks were as a rule carried on to the ground as soon as they were fairly dry and firm, and were laid while still soft.