Nevertheless, Basra overcame these natural disadvantages and rapidly grew into the second-largest city in Iraq, if not the entire Islamic world. Its role as a military encampment meant that the soldiers had to be fed, and since those soldiers were receiving government salaries, they had money to spend. Thus, both the government and private entrepreneurs invested heavily in developing a vast agricultural infrastructure in the Basra region. These investments were made with the expectation of a profitable return, indicating the value of the Basra food market. Although Zanj slaves from Africa were put to work on these construction projects, most of the labor was done by free men working for wages. Governors sometimes directly supervised these projects, but usually they simply assigned the land while most of the financing was done by private investors.