"In 762, to symbolize and propel the new order, decided to build the grand new capital of Baghdad as a massive round city. The caliph assembled an elite team of the empire’s top engineers, architects, and visionaries—notably including Zoroastrians, Christians, and Jews, such as Mashallah Ibnul-Athari."
January 1, 1970
https://en.wikiquote.org/wiki/Baghdad