What was the Chaldean economy based on?
Ummm….the very first google search under “Chaldean economy” “The economy rested upon agriculture, but governance, industries and fine arts were carried out in the cities.” “The most important industry of Babylonia was agriculture, but other industries were fairly well developed too. Babylonia was involved in foreign trade, and exported manufactured goods, while the country had to import metal, wood and stone — materials that the country lacked.” http://lexicorient.com/e.o/babylonia.htm As for what particular industries they relied upon, I don’t know. Here is another link for you, under googling “early Babylon economy”.
