Medieval Islamic Conquest

While poking around some of my medieval stuff, I came across some descriptions of the Islamic conquests. One of the factors that facilitated the success of the spread of Islam in the 7th and 8th centuries was that the Byzantine and Persian empires had beaten each other up so much that they were weakened. In the case of the Byzantines, this meant less attention paid to the Western Empire, which had actually ocurred after Justinian. The Persians were similarly ignorant of what Mohammed was doing in their backyard. Thus, Islam rose up and expanded in the wake of a war between two medieval super powers. This struck me as at least tacitly similar to Bin Laden's call to establish the Caliphate in the wake of the Cold War. Just a thought....