The Iraqi revolt of 1920 was a watershed event in contemporary Iraqi history. For the first time, Sunnis and Shias, tribes and cities, were brought together in a common effort. In the opinion of Hanna Batatu, author of a seminal work on Iraq, the building of a nation-state in Iraq depended upon two major factors: the integration of Shias and Sunnis into the new body politic and the successful resolution of the age-old conflicts between the tribes and the riverine cities and among the tribes themselves over the food-producing flatlands of the Tigris and the Euphrates. The 1920 rebellion brought these groups together, if only briefly; this constituted an important first step in the long and arduous process of forging a nation-state out of Iraq's conflict-ridden social structure.