In his Introduction Michael Decker notes the "remarkable longevity" of Byzantine society and the fundamental role of the military in that longevity (viii). He further comments that while attribution of a "grand strategy" to the Byzantines is doubtful, there are "patterns to their approach to warfare" which can be described as "the Byzantine Art of War," whose parameters he seeks to describe (ix). In subsequent chapters the author provides a Historical Overview (Chapter 1), followed by chapters on Leadership, Organization, Recruitment and Training (Chapter 2), Equipment and Logistics (Chapter 3), Strategy and Tactics (Chapter 4), Enemies of Byzantium (Chapter 5), and the Byzantine Army at War (Chapter 6), culminating in a chapter entitled "The Byzantine Art of War" (Chapter 7). He also indicates that the book is written for a "non-specialist audience and students of military history" (presumably undergraduate college students) (ix). There are eleven maps.
Chapter 1 begins with the consecration of Constantinople in 330 and concludes with the fall of the city to the Ottomans in 1453. While obviously a highly compressed summary, the topics included are well chosen and at times presented with surprising detail, although some periods receive perfunctory treatment The character of Julian, for example, his motives for the Persian campaign of 363, the specifics of the march to Ctesiphon, the subsequent retreat and its disastrous consequences are described and narrated accurately and effectively.
Chapter 2 extracts from military manuals, particularly the Taktika (ca. 903) of Leo VI, the prescribed qualities of a good general (among them piety, fatherhood and aristocratic origin), notes the lack of value placed on initiative from the lower ranks, and finds experience as the primary teacher of combat leadership. Three military 'biographies,' of Belisarius, and of the emperors John Tzimiskes and John II Komnenos, are employed to illustrate key leadership qualities: cool-headedness under duress, caution in the face of the enemy, and a thorough understanding of strategy, tactics, operations and logistics. Tzimiskes' defeat of the Rus' under Sviatoslav in 970 at Dorystolon in Bulgaria (modern Silistra) provides examples of that emperor's tactical expertise in the use of heavy cavalry and decisive personal intervention at a critical moment in the battle.
Chapter 3 examines (ca. 300-1388) the evolution of the organizational structures inherited from imperial Rome, admittedly a daunting task in twenty-six pages. Decker credits Constantine I as source of "radical structural changes", while noting Diocletian's role in creating a "new imperial bodyguard" (68-69). The relative contributions of the two emperors would benefit from more in-depth analysis.  The role and effectiveness of the frontier forces (limitanei) and their relation to the regional field armies (comitatenses), another complex issue, might also have been afforded more nuanced treatment. Fuller discussions are provided of the thematic armies, the tagmata ("regiments"), and the increasing importance of tagmatic forces in the tenth and eleventh centuries. The subsequent sections on recruitment and pay are generally accurate and informative.
Chapter 4 nicely describes the distribution, locations and organization of arms factories, the distances and road networks over which supplies were brought, the installations including warehouses along the routes and the imperial post system which provided communications. Tenth-century inventories are cited for evidence of the methods of logistical planning for military expeditions. Specific articles of clothing and defensive body armor, as well as helmets and shields, are characterized in some detail; likewise offensive weapons: spears, swords, mace, battle-axe, and various missile weapons. A brief section on artillery notes the likely end of torsion weapons by the close of the sixth century and the appearance in Byzantium of the traction trebuchet.
Chapter 5 argues that while there is no evidence of any "standing central command responsible for long-term strategic planning" or an articulated strategy for preservation of the borders, a frequently employed set of practices can be discerned which, following Edward Luttwak (but with some differences), might be called "Grand Strategy" (131). The practices described here include being always prepared for war, using spiritual and psychological motivations, finding allies, fighting wars of attrition, border "defense in depth," fighting small wars, and using diplomacy to divide and conquer. The attribution of a "grand" strategy in any form, however, remains contentious and the political and propaganda needs of individual emperors often played a significant role in military decisions.  The section on "defense in depth" (140), a phrase strongly associated with Luttwak and highly controversial, presents one side of the theory, permanently garrisoned, self-contained border fortresses and fortified towns, but does not include the other, accepting incursions as inevitable but delaying the invaders and depriving them of supplies until mobile forces (comitatenses) could arrive. Discussions of espionage and intelligence, including strategic and battlefield intelligence, are followed by elucidation of tactics where Decker rightly asserts the continuing significance of the infantry in the sixth century, the increased importance of light cavalry following the Arab conquests, and the return of infantry to greater significance by the tenth century (particularly the menavlatoi or pike men) as part of a combined arms approach. The section on siege warfare rightly notes the strong preference for use of treachery or starvation to take a walled city; where necessary in the tenth and eleventh centuries the Byzantines resorted primarily to sapping operations or assaults with ladders aided by covering fire from archers, slingers and traction trebuchets.
Chapter 6 discusses some of the major enemies of Byzantium--Germanic peoples, Persians, Arabs, Bulgars and Normans (but oddly not Turks)-- in terms of military organization, methods of warfare, and the Byzantine adaptation to their methods. Decker argues that the majority of Goths at Adrianople fought as infantry spearmen and swordsmen, estimating Goth forces at that battle as 5000 cavalry and twice as many infantry, but by the sixth century Goth cavalry constituted a greater part of their forces. The Byzantine approach to dealing with them following Adrianople was by treaty and recruitment into the Byzantine army as federates, also countering their influence with recruitment of Isaurians from Asia Minor as rivals, as well as movement to Italy under Theodoric. The Persians are characterized as "the most...militarily threatening power" of the early period, an enemy that favored massed cavalry assaults and possessed excellent technical siege capabilities (165). The author notes that when Byzantines were able to choose the battlefield they could successfully counter Persian strengths. Steppe nomads, particularly Huns and Avars, are characterized as "lightly armed horse archers"(168), from whom the Byzantines adopted the stirrup and other equipment and tactics and to whom they often paid subsidies rather than confront militarily. The preponderance of Arab infantry archers and spearmen during the initial conquests is noted, and the subsequent coordinated mix of infantry and cavalry with the presence of Bedouins on swift Arabians horse. The Byzantine response was tribute payment, avoidance of large-scale confrontation, and guerilla tactics of shadowing and harassment against Muslim raiders until the offensive Byzantine campaigns of the tenth century. The Bulgars are characterized as possessed of high levels of planning, discipline and cohesion as exemplified by their defeat of the emperor Nikephoros I at the Varbica Pass in the Balkan Mountains in 811. The Byzantine response over time is characterized as a combination of measures--economic (designated trade zones), diplomatic (inducing the Rus' to invade Bulgaria), and military (Basil II's conquest via sieges and attrition). The Normans are shown as primarily infantry spearmen fighting in support of cavalry, namely knights in mail armor whose shock charge was often decisive. The Byzantine response included use of Italian and German allies, avoidance of large-scale confrontation, and use of archers to shoot Norman horses and then kill their riders.
Chapter 7 explicates the Byzantine army at war through an analysis of major campaigns (the Vandal War, the Eastern campaigns of Nikephoros II), individual battles (Kleidion 1014, Sirmium 1167), and siege warfare, both defensive (Constantinople 626, 667-673, 717-718) and offensive (Crete 961-962, Anazarbos 1137). The Vandal War provides a good example of a long-range expedition. Belisarius' invasion force, characterized as "impressive but not overwhelming", is detailed in terms of numbers: 15,000 troops, 500 transport ships with 30,000 sailors, 92 escort warships with 2000 marines. Four maps provide analysis of the battle of Ad Decimum. Nikephoros II Phokas's campaigns include a description of his battle before Tarsos in 964 (citing text from Leo the Deacon), which featured cataphracts in the van while archers and slingers fired from behind causing the Tarsians to turn to flight and the subsequent siege which ended as starvation set in. Decker's account of the battle of Kleidion in 1014 is set in the historical context of Bulgar-Byzantine relations from the seventh century onward and details the confrontation at the pass of Kleidion where the Bulgarians used wooden palisades to block the Byzantine advance. After a number of failed assaults the Byzantines found a route through the mountains and attacked from the rear with decisive results. An excessively lengthy discussion of the reign of Manuel I Komnenos (1143-1180), including troubled relations with Hungary, sets the scene for what we are told via a heading is "The Battle of Semlin, 1167" (198). No battle is described in this section, however, but the battle in question oddly does appear in what follows under the next heading "The Battle of Sirmium, July 8, 1167" (202), albeit under the different name.  This is one of a number of indications of poor copyediting. In the battle an apparently a feigned retreat on the part of the Byzantines left wing enabled them to envelop the Hungarian forces and which led to their rout. The chapter concludes with a series of examples of siege warfare. The Arab siege of Constantinople in 717-718 is described with a trench and wall on the Thracian landward side and by sea an Arab fleet of reportedly 1800 vessels. The use of Greek fire to destroy many Arab ships, including supply ships, combined with the aid of Bulgar allies in both preventing Arab foraging and subsequently attacking in force, ended the siege. The siege of Candax on Crete by Nikephoros II Phokas (960-961) provides an example of fully armed cavalry disembarking via ramps ready for combat, construction of a palisade to prevent resupply of Candax by sea, use of traction trebuchets against the defenders on the walls, and a successful sapping operation. Finally John II Komnenos' siege of Anazarbos in 1137 breached the walls with counterweight trebuchets, protected behind earthworks and clay bricks. This wall-breaking artillery continued to be successful in John's subsequent campaigns and indicates the significant change in siege methods over traction trebuchets.
Chapter 8 examines Strengths, Weaknesses, Why the Empire Fell, Byzantine Contributions to Warfare, and the Overall Legacy. Among the strengths Decker finds the high value placed on "conservation of forces" based on Byzantine knowledge of their forces' limits and difficulty of replacing skilled soldiers (214). Also among the strengths were the core belief that the empire was "ordained and supported by the Christian God," which allowed recovery from severe defeats, and the ability "to adapt, to learn from the enemy, to modify tactics" (215). Among the weaknesses he finds its geopolitical position (having to deal with threats on three fronts simultaneously), the failure to adapt technologically and numerically to the Norman knight, and internal divisions among the military aristocracy in the eleventh century. He suggests as causes of the fall of the empire the power of the hereditary aristocracy resulting in the loss of opportunity for upward mobility and the impoverishment of the (tax- paying) peasantry, thus starving the state of resources and manpower. He also notes a decline in the quality of local troops, the cost (but not loyalty) of mercenaries, and the consequences of the Fourth Crusade which led to the Greek successor states led by petty dynasts. Among Byzantine contributions to warfare he suggests further diffusion of the stirrup (which the Byzantines themselves adopted from the Avars) and likewise the traction trebuchet. Regarding original inventions he includes Greek Fire (the ship-borne force pump version) and the hand-held flamethrower, as well as the counterweight trebuchet. He further notes the difficulty of tracing the Byzantine legacy in the history of warfare. One exemplary vignette found in Anna Komnene's Alexiad describes her father the emperor Alexios providing a meeting of the leaders of the First Crusade detailed information on how to fight the Turks. The extent to which the advice was taken is unknown.
The vast scope of the topic and the physical limits of the volume inevitably require compression of complex issues with some questionable assertions and omissions of significant material. On page 2, for example, the reference to Constantine's restoration of Trajan's bridge over the Danube at the Iron Gates and its symbolic significance is debatable. Constantine had his own bridge built at Sucidava-Oescus, dedicated in 328; its propaganda value to him, as a rival of Trajan, was significant. Whether he also restored Trajan's bridge, while possible, remains theoretical.  Despite some of the problems noted the book has much of value and will generally provide its stated audiences a valuable introduction to Byzantine warfare.
1. See on the role of Diocletian, for example, A. Poulter, "The Lower Danubian Frontier in Late Antiquity: Evolution and Dramatic Change in the Frontier Zone, c. 296-600," in P. Herz, et al. (eds.), Zwischen Region und Reich: das Gebiet der oberen Donau im Imperium Romanum (Berlin: Frank & Timme, 2010), 11-42, esp. 16.
2. See P. Heather, "Holding the Line: Frontier Defense and the Later Roman Empire," in V. Hanson (ed.), Makers of Ancient Strategy: From the Persian Wars to the Fall of Rome (Princeton: Princeton University Press, 2010), 227-246.
3. For "Semlin in the district of Sirmium" and the battle see J. Haldon, The Byzantine Wars: Battles and campaigns of the Byzantine era (Stroud, Gloucestershire: Tempus, 2001), 193-195.
4. See D. Bondoc, The Roman Rule to the North of the Lower Danube during the Late Roman and Early Byzantine Period (Cluj-Napoca: Mega Publ. House, 2009) 139-140.