William Muir,
The Caliphate: Its Rise, Decline and Fall…
“ At Al-Kufa the races coming from the south of Arabia predominated; at Al-Basra, those coming from the north. Rapidly they grew into two great and luxurious Capitals, with an Arab population each of from 150,000 to 200,000 souls. On the literature, theology, and politics of Islam, the two cities had a greater influence than the whole Muslim world besides. There was abundance of time and opportunity. Service in the field being desultory and intermittent, the intervals were often long and frequent, but too readily spent in listless idleness. ”
