It is an inconvenient fact—and one studiously neglected by proponents of unrestricted global migration—that the main military participants in the politically incorrect and toxically masculine medieval Crusades were migrants. Nubian infantry, Egyptian cavalry, Armenian Turcopoles, European knights, and Turkic horsemen from the Eurasian steppes all migrated to the Levant during the High Middle Age period covered in Steve Tibble’s new book.

Within a generation of the First Crusade, intermarriage yielded new natives to the Eastern Mediterranean. The blood of Greeks, Syrians, Armenians, and Western European Christians mixed and helped form a distinctive Frankish culture in the crusader states of Antioch, Tripoli, Jerusalem, and Edessa. And, perhaps to a different degree, a similar mixing occurred amongst the Muslim Arabs, Anatolian Turks, Armenians, Turcomans, and Egyptians.

The Levantine East had always been a crossroads of continents. Ancient trade routes carried merchants, goods, ideas, and religions to all points east and west, north and south. For centuries, cities like Aleppo, Homs, and Edessa were cultural and religious melting pots. The arrival of European crusaders, therefore, should be seen as part of a continuum rather than as a destructive irruption upon a homogenous culture.

It is a testament to the willful ignorance of the media and political elites that historians of the Crusades continue to churn out myth-busting books. Any casual student of Crusades history, which is Tibble’s intended audience, knows that popular understanding has lagged behind scholarship in recent decades.

The Crusader Armies offers more than the obligatory corrections to the historical ignorance of our age. It is a full-scale reassessment of the warfare, armies, and enemies of the Western Crusades in the Middle East.

Tibble’s focus is seemingly narrow. He is concerned only with the first 88 years of the Frankish kingdoms of the Latin East. He does not substantively address 13th-century crusader activity, the Baltic Crusades, the Iberian Reconquista, or the Albigensian Crusade. But his seemingly narrow focus is deceptive. The period he covers, from the First Crusade to the Battle of Hattin, saw some of the most significant changes to warfare in the Levant, changes that echoed beyond the Holy Land to Western Europe. “Warfare in the east,” Tibble argues, “was a crucible of innovation for European warfare, leading developments, not typifying or reflecting them.”

The innovations that resulted from the West’s medieval encounter with the Levant applied to all aspects of warfare and administration: financing, castle construction, weaponry, armor, and recruitment. It was especially true with regard to filling the ranks. For example, lepers were allowed to join their own fighting order. A Templar or Hospitaller knight who contracted leprosy was transferred to the Order of Saint Lazarus, a military order specifically for leprous knights. Indeed, manpower was at such a premium for the Franks that lines between heavy and light cavalry and infantry were not always as clearly drawn as they were in continental European armies.

Necessity drove innovation. Innovation allowed crusader armies to adapt to new and varied threats. This was demonstrated in the effectiveness of Frankish sieges on the Levantine coast. The Franks organized joint operations with naval forces from Genoa, Pisa, and Venice to successfully attack coastal installations of the Fatimid Caliphate. But the further inland the enemy fortification, the less successful the crusaders were.

Three tactical developments typified crusader warfare: the Frankish heavy cavalry charge, fighting march, and infantry shield wall. And while these were not exclusive to crusader armies, they were used differently and to greater effect than elsewhere. For example, Tibble argues that infantry had more prominence in the crusader states than in Europe because they were essential to protecting Frankish heavy cavalry. Infantry units screened cavalry on the march and in battle from enemy archers. They were therefore better equipped and trained and had a higher social status.

Nowhere was the need for innovation greater than in Frankish battles with Turcoman tribes. The Turcomans—as distinct from their settled Anatolian cousins—were “nomadic” or “nomadic heritage” warriors who brought culturally discrete practices and fighting skills to the Middle East. Bursting forth from the Asian steppes in the 11th and 12th centuries, they were expert horseman and archers. Known for exceptional speed, maneuverability, and ferocity, they provided a ready and almost inexhaustible source of mercenaries for the Muslim armies of the Levant. Small groups also served as light cavalry and scouts for Christian armies as well. But they posed the greatest challenge to Frankish commanders, who never quite found a way to successfully counter their strategic advantage in numbers and tactical dynamism.

Tibble argues that these “cultural asymmetries”—which he believes were the result of climate-change-driven mass migration—are best understood as part of a larger clash between sedentary and nomadic societies. Despite some arguable points, it is a useful framework. Not least because it applies equally to the Turkic warriors’ clashes with their Muslim co-religionists in Fatimid Egypt. Tibble demonstrates to great effect how Frankish forces bested Fatimid armies in pitched battles. This was, he argues, a clash of culturally symmetrical forces, in that both the Franks and Fatimids originated from sedentary societies, which did not require much adaptation for the Franks. The Frankish failure to find a strategic answer for numerical inferiority and an effective tactical response to Turkic horse archers contributed greatly to the demise of the Crusader states. Thus, Tibble concludes “climate change and massive migration crises were fundamentally far more important than religion in shaping warfare in the region during the period of the [C]rusades.”

Of course, one may take exception to the notion of climate change as an explanation for the massive migration of Turkic tribes. And surprisingly, Tibble offers no evidence for it. But it isn’t fatal to his argument. It is not significant to a military history of the Crusades why the Turcomans came west—only that they did. That they were nomadic horsemen possessed of exceptional war-making ability is significant and tells us much more about the cultural asymmetries that Tibble compellingly highlights. As nomadic warriors, it is quite likely they would have wandered wherever the plunder was plentiful, regardless of climate.

Tibble’s analysis of the armies of the Crusades and the patterns of warfare between them is sharp and amply supported by the sources. He relies on well-known Christian chroniclers Walter the Chancellor and William of Tyre, as well as Muslim chroniclers like Usama ibn Munqidh and Ibn al-Qalanisi. He consistently reconciles these and other contemporary accounts to arrive at a plausible understanding of troop strength, army movements, and battles, as the medieval chroniclers are often more entertaining than accurate. While acknowledging the many gaps in extant documentary sources, Tibble excels in attempting to fill them with inferences drawn from archaeological and architectural evidence.

He also discredits much of the modern narrative that surrounds the Crusades. Thanks to works such as Ivanhoe in literature and Kingdom of Heaven in film, and to the persistent banging on of progressive elites about crusaders as “colonizers,” falsehoods about the crusading era abound and retain, as Tibble sees it, a “superficial plausibility.” Historical evidence offers a very different picture, and Tibble makes it abundantly clear that “none of the armies of the crusader period corresponded to the easy caricatures painted of them.” He writes that, “Rulers of the crusader states did not impose an intolerant tyranny on the majority of the population.” Rather they generally enjoyed “harmonious relations.”

Also, armies were not ethnically or religiously monolithic. Nor were battles exclusively fought between Christians and Muslims—much of Saladin’s military efforts were in fact directed toward killing fellow Muslims. An interesting example is the role of black infantry in the Fatimid army. The Sudani were sub-Saharan Christian slaves or mercenaries segregated from other divisions who fought for the Shiite Muslim caliph. They were subject to what might be called today “institutionalized racial prejudice,” i.e. they were never promoted in the ranks and were treated as expendable. On numerous occasions they were abandoned to die on the field by their Muslim commanders.

Tibble’s work makes him an academic descendant of other Crusades historians such as R.C. Smail and Jonathan Riley-Smith. He also stands in good company with accessible Crusades historians like John France and Malcolm Barber. The Crusader Armies is readable, expertly sourced, and well organized. It isn’t the last word on the subject, but it is likely to be the best one for quite some time.

[The Crusader Armies: 1099-1187 by Steve Tibble; New Haven: Yale University Press; 424 pp., $35.00]