Since Samuel Huntington unveiled his “Clash of Civilization” thesis in a 1993 Foreign Affairs article, a cottage industry of critiques have emerged to challenge it. Great thinkers, such as Amartya Sen, Amin Maalouf and Edward Said, have expended time and ink to refute Huntington’s controversial thesis. For the most part, these works have presented rationale critiques that focus on theoretical problems raised by Samuel Huntington’s board game like simplification of geopolitics and global history. Few of these critiques have, however, tried to counter Huntington’s argument with primary source research or been as readable as Ian Almond’s Two Faiths One Banner: When Muslims Marches with Christians Across Europe’s Battlegrounds (2011).

In this slim book, Almond shows that European history is far more muddled than Huntington’s depiction of one overarching “clash” between two visions of Abrahamic monotheism. Indeed the individual motivations and allegiances proves far to complex to paint with even the most vivid neoconservative or Marxist brush strokes. In making this argument, Almond cuts across wide historical periods, as well as the politics of several different centuries, demonstrating a mastery of facts, figures and a flair for colorful details.

The success of Almond’s argument lies in its exclusive focus on military campaigns and the colorful historical figures associated with these efforts. Beginning in eleventh century Andalusia and ending with the Crimean War in the mid-ninenteenth century, the book examines periods in which Muslim and Christian groups were fighting together rather than against one another in various battlefields. Rather than antagonistic civilizations, Almond’s reading of history suggests that individual units and individuals often had distinct allegiances that would surprise those eager to fit the world into neat left-wing or right-wing paradigms.

The military campaigns covered in the book include some of the most important in history. Muslims and Christians not only pop up in a number of Europe’s most decisive battlefields but also figure in both sides of the fighting. For example, during the Siege of Constantinople in 1453 a small group of Turks fought with the city’s Christian defenders for political reasons. At the same time, the Ottoman Sultan Mehmet II’s force included some Christian contingents while several Ottoman advisors were seemingly against any attack on the city; these strategists preferred retaining a weakened enemy as a buffer state around their emerging empire, a geopolitical strategy long perfected by the Byzantines themselves.

The 1683 Ottoman siege of Vienna also featured a similar comingling of Christian and Muslim fighters. The Ottoman army “at the Gates of Vienna” consisted primarily of Christian military men. Indeed, one of the important figures in the Ottoman campaign was the Hungarian Protestant Prince Imre Thököly. Thököly’s support of the Ottomans briefly inspired the English-language word “Teckelite,” a disparaging term used in seventeenth century England for a pro-Ottoman Protestant or fellow traveler.

In addition to the ill-fated Prince Thököly, Almond’s book is full of interesting figures. Among these is the hard charging nineteenth century Polish Cossack officer Michał Czajkowski who galloped across Europe’s battlefields as well as between its religions. Czajkowski routinely changed faiths, converting to Islam as well as to competing forms of Christianity. Czajkowski’s ever changing religious convictions speak more of his political opportunism than of any heartfelt change in religious belief.

Better known historical figures, such as the German poet Goethe, also make cameos in Almond’s book. In 1813, a Russian army outfit with a contingent of Bashkir Muslims was marching westward through Germany. While the army was encamped in the town of Weimar, Goethe oversaw the conversion of the local Protestant school into a makeshift mosque and hosted some of the Muslim officers in his home for tea and cake. The Russian Muslims went on to participate in the Battle of Leipzig against Napoleon, the largest battle fought in Europe prior to the First World War.

For Almond, such cooperation between Muslims and Christians has too often been ignored in formulating popular understandings of history. For example, the author points out that Muslims played a significant role in the Battle of Balaclava during the Crimean War. During this engagement, a hastily drawn up Allied line successfully defended against an assault from a larger Russian force. The forces that formed the line included the Scottish 93rd Highland Regiment as well as a large Ottoman contingent. As Almond puts it, “In other words, half of that ‘thin red line,’ probably one of the most famous military phrases in the English language, was Muslim.” Indeed, the “thin red line” has become an apropos metaphor for a small but determined force facing great odds and has lent itself to the title of an engaging James Jones novel (itself later a thoughtful Terrence Malick film).

Of course, no work on European historical interfaith issues would be complete without an obligatory chapter on Andalusia. Which has become a biword for multiculturalism though conceiving of Al-Andalus in that way is a bit anachronistic. Almond includes a discussion of the region’s warlords and intrigues while also addressing more obscure topics such as the Catalan-Muslim alliances of the thirteenth century. Almond also discusses the influences of the Kingdom of Aragon and Catalan across the Mediterranean, a topic that has typically received little attention from scholars.

Although the book ends with the Crimean War, Muslims did not stop participating in European wars at that juncture and fought on both sides in the various world wars. Perhaps the highest-ranking Muslims of the Second World War were found outside Europe. For example, the Chinese army included such famous generals as Bai Chongxi and the famous “Ma clique.”

Edward Said might have been disgruntled to find that orientalist views of certain key figures facilitated the crafting of Christian-Muslim alliances. For example, the Arabic-speaking Holy Roman Emperor Frederick II led a successful but forgotten crusade shortly after Saladin captured Jerusalem. Frederick was fascinated by Arab Muslim culture and adopted many customs from Arab kingdoms. In fact, a contingent of Arab Muslims from Sicily joined his ultimately successful crusade.

Similarly, the British officers sent to organize the Ottoman Empire’s irregular troops in the Crimean War were selected because they had spent time on the Indian subcontinent in the belief that the “Arab mentality, presumably, [is] no different than the Indian one.” Surprisingly, however, many of these British officers actually showed a deep cultural understanding in leading their Turkish, Kurdish and Arab troops. In one instance, British officers used an English-language translation of the Koran and employed Islamic reasoning to convince their Ottoman soldiers that they would be exempt from the Ramadan fast during wartime. One might wonder if these British officers ever used the Crown’s own links to the Prophet of Islam to inspire their Muslim soldiers.

No single factor explains the historical alliances discussed by Almond. Opposition toward a common enemy or common affinities during years of shared cohabitation were likely factors in many historical examples. Karl Marx would surely add material gain to the list and Adam Smith might point out that these alliances created competitive advantage over rivals who took a less realpolitik approach to statecraft.

Almond is at his best, however, when he leaves conjecture to the reader and merely lets the primary documents speak for themselves. What went through the minds of the Muslims who marched with Frederick II to recapture Jerusalem in the name of Christendom? Did the Turkic Muslims in the Russian army ever feel conflicted about fighting their coreligionists from the Ottoman Empire? Rather than coming up with new explanatory frameworks, Almond’s book teaches us to appreciate that the different political interests and intrigues of individuals are far too complex to fit into Huntington’s “Clash of Civilizations,” Edward Said’s Orientalism (1978) or any other backwards looking philosophy.

This story first appeared at America’s Future Foundation’s Doublethink blog, June 14, 2013.