300 to 500 years earlier, the population for the whole of Mesopotamia was at its all-time high of about 300,000. Elamite invaders then toppled the third Dynasty of Ur and the population declined to about 200,000; it had stabilized at that number at the time the relief was made. Cities like Nippur and Isin would have had on the order of 20,000 inhabitants and Larsa maybe 40,000; Hammurabi's Babylon grew to 60,000 by 1700 BCE. A well-developed infrastructure and complex division of labour is required to sustain cities of that size. The fabrication of religious imagery might have been done by specialized artisans: large numbers of smaller, devotional plaques have been excavated that were fabricated in molds.