The Great Arab Conquests: How the Spread of Islam Changed the World We Live In
By Hugh Kennedy
Weidenfeld & Nicolson £25, 448 pages
FT bookshop price: £20

Last September, Pope Benedict XVI ignited furore across the Islamic world when he repeated a statement made by a Byzantine emperor in the 14th century: “Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached.”

Only after the controversy was under way did the Pope make clear that he disagreed with the assertion. He had, however, pointed out in his speech that the Koran contained contrasting views on the question of whether unbelievers should be compelled to convert to Islam or whether, as one verse says: “There is no compulsion in religion.”

Early verses of the Koran included moderate verses, which urged conversion by discussion. The dominant opinion among scholars, as Hugh Kennedy notes, is that only later were verses incorporated that urged unrestricted warfare on unbelievers. The implication is that these more peaceful verses emerged at a time when Mohammed’s own position was insecure. The more strident passages date to when he was leader of a successful military force.

Mohammed’s military campaigns ensured from the outset that armed force would be an acceptable way to defend the new religion and, later, to expand it. They blocked any tendency towards the pacifism that had marked early Christianity. They also provided a model for the Arab conquests which followed his death and took Islam as far as both China’s borders and France within 100 years.

The story of this extraordinary expansion is well told in this excellent book. Not least, the account helps explain many of the current borders of the Muslim world. It also provides the early context for religious ideas that continue to motivate believers. Of these, the most controversial is that of jihad. From the outset there were differences about what it means – whether it has to be violent or can be spiritual, whether it is obligatory or voluntary and whether it is merely defensive or can be expansionary. This debate still reverberates today.

In fact, Mohammed’s own success was not based simply on military victories. Kennedy, professor of history at the University of St Andrew, points out that diplomacy was more important in securing the allegiance of people in Yemen and Oman. Yet, when Mohammed died in 632, the future of Islam was in the balance.

According to Kennedy, the proponents of the new religion were forced to look outward from the Arabian peninsula. Muslims were forbidden from attacking each other. But the Bedouin way of life had been based on frequent raids of neighbouring tribes. The choice was either to expand beyond Arabia or see Arabs fall back to their pre-Islamic tribal rivalries.

The key to their extraordinary success lay neither in technological superiority nor in innovative tactics. It was due to events elsewhere in the first three decades of the seventh century. The two great imperial powers of the day – the Persian and Byzantine empires – had exhausted each other in military campaigns that saw early Persian successes reversed by later Byzantine victories. If the Arab military effort had begun three decades earlier, it surely would have failed. Yet the deal the Arabs offered their adversaries – surrender, pay us tribute and we’ll allow life to continue much as before – meant they conquered swathes of territory without a fight.

The sources for any work on this subject are often sketchy and contradictory. Kennedy frequently has to rely on accounts made even centuries after the events they describe. When sources are more contemporary, they are regularly concerned with tales of how the booty was shared afterwards, not with the facts of battle. As such, Kennedy makes plain that his descriptions are often no more than a best guess. But it is an approach that provides the reader with a well-paced narrative that does not compromise on academic rigour.

Most of the focus of the book is on the expanding edge of the empire. What is not made clear is how that expansion related to events at the centre. In particular, the rivalries that led to the great divide between the Sunni and Shia are only touched upon. The lack of information on these power struggles leaves the reader wondering how, if at all, they shaped the conquests.

This is, nonetheless, a highly-readable account of remote events that still have a striking relevance for the shape of our modern world.

Stephen Fidler is the FT’s defence and security editor