Readers may be familiar with the fundamental changes that took place in the Roman world as it converted from paganism to Christianity in the fourth century, and as its emperors sought to govern, through the turbulent times of the fifth to seventh centuries, as Christian rulers. This is the stuff of late antiquity as it would be recognised in any classics or history university department. It is, as Tom Holland points out in the opening pages of his latest book, a period of fundamental importance for the shape of our world, as it is the era in which religious monotheism, rather than political kingdom, comes to dominate history. In that context, Holland focuses on the birth of Islam through the prophet Mohammed in Mecca and Medina (modern-day Saudi Arabia) during the course of the seventh century, as it is told to us by one of Mohammed’s biographers, Ibn Hisham, in the ninth century. The faith of Islam, as Holland points out, is centred on the study and strict observation of both the divine revelations to Mohammed (the Koran), and how Mohammed acted during his lifetime (the Hadith and the Sunna). Yet, echoing what many (mostly non-Muslim) scholars have queried before, Holland points to the historical problem of the evidence: before 800AD, almost 200 years after Mohammed’s death in 632AD, the only “traces we possess” for the development of Islam “are either the barest shreds of shreds, or else the delusory shimmering of mirages”. The task Holland sets himself is to ask what can be done about that gap. His answer is to approach it from the opposite direction: to approach the origins of Islam from its recent past, from the world of fifth to seventh century late antiquity. “Is it possible,” he asks, “that Islam, far from originating outside the mainstream of ancient civilisation, was in truth a religion in the grand tradition of Judaism and Christianity – one bred of the very marrow of late antiquity?” Holland examines late antiquity not as an age of decline and fall, but of energy and inventiveness, setting the Arab world and Mohammed’s life in the context of the changing geographies, cultures and priorities of the empires of Rome around the Mediterranean, the Sassanians to the East, and the religious and cultural melting-pot of the “Holy Land”, which connected them. Holland identifies key events, places, ideas and decisions within the Persian and Roman systems which may have impacted upon the Arab world, and, in turn, on the birthplace of Islam in Mecca and Medina. In so doing, Holland argues for the forging of Islam in the political and military instability and opportunity of a world convulsed by a changing balance of power. The process, he continues, ensured that, by the ninth century, “a version of Islam’s beginnings that gave no scope for anyone to rule as a Deputy of God”, and in turn no room “for acknowledging the momentous role in the forging of Islam by countless others”, had gained acceptance, the continued presence of which, inevitably, makes Holland’s thesis difficult reading for an Islamic audience. Focusing on the wider context to unpick key moments in history is a classic Holland approach, echoing, for example, his study of the fifth century BC Persian invasion of Greece in Persian Fire (2005), which explored the context and prior history of the Persian and Greek worlds. Such an approach is now in vogue, because it demands that the historian break the often stifling disciplinary boundaries that have traditionally governed the study of worlds which knew no such boundaries. This is a handsome volume, tackling an important question from a novel perspective, backed by useful notes and written in an accessible and fluid style. But, as I am sure Holland would accept, in part because of the charged nature of the material and issues on which it dwells, and in part because of the vast developments and arenas it attempts to encompass, it is also bound to encounter the full spectrum of critical reaction.