In the history of warfare, The Iliad apart, sieges have tended to appear less glamorous or decisive than pitched battles. Yet success or failure in seizing enemy cities has proved militarily pivotal: in modern times, think of Leningrad or Stalingrad. In the Middle Ages, sieges of towns and castles dominated military strategy and practice in western Europe. Of the thousands of medieval sieges, one stands out. The siege of the Levant port of Acre (modern Akko in Israel) lasted 653 days, from August 1189 to July 1191, becoming one of the longest sieges in medieval European and Mediterranean history. By comparison, the lengthiest siege in English history, of Kenilworth Castle in 1266, occupied just under six months, while the Ottoman siege of Constantinople in 1453 took a mere seven and a half weeks.

The struggle to capture Acre formed the opening military passage of the Third Crusade in Palestine. It involved armies from across western Europe, the Mediterranean, northern Africa and the Near East, pitting rulers and great lords from England, France, Germany and Italy against those of Egypt, Syria and the Jazira. The leading figures on both sides, most notably Saladin and Richard the Lionheart, soon acquired legendary status. Acre had first been occupied by crusaders in 1104. It surrendered to Saladin during his lightning conquest of Palestine and the Lebanon in 1187. For the crusaders, the city was important both as a naval base for future operations and as a hugely lucrative commercial entrepôt. One participant in the siege noted, ‘if the ten-year war made Troy famous, then Acre will certainly win eternal fame’.

This was not much of an exaggeration. The siege attracted extensive eyewitness commentary on both sides and intense interest later across Christendom and the Near East among chroniclers and historians, poets and artists. They cast the siege as an epic of religious confrontation, the stakes raised by its long duration, the acute privations suffered on all sides, the great figures involved and the unusual configuration of the crusader army, many thousands strong, whose massive losses through battle, malnutrition and disease were regularly replaced by new arrivals by sea. For long periods, the crusaders remained precariously encamped between the city’s defences and Saladin’s field army, creating a sustained intimacy of conflict with unique dramatic potential.

Recent archaeological and topographical research has deepened our understanding of the physical setting of the siege. In this pleasingly concise book, John D Hosler, a medievalist teaching at the US Army Command and General Staff College at Fort Leavenworth, Kansas, skilfully weaves this material into a concentrated, detailed, day-by-day, blow-by-blow narrative. His descriptions are at close quarters, vivid, human and humane. Hosler has a firm grasp on the physical experience and a clear understanding of the local terrain, the desperation of battle, the agonies resulting from repeated depletions of food supplies and the squalor of and camaraderie in the besiegers’ trenches. Individual vignettes are sharply polished – one such describes Emir Husām accidentally spilling ‘Greek fire’ (a highly combustible mixture of crude oil and naphtha) onto his testicles.

Hosler’s day job is on show in some of his language (‘the crusaders engaged in sync and rhythm’), his attention to tactics and leadership, his judgements on generalship (he gives low marks to Saladin, higher grades to Philip II of France, and sends Richard I, who arrived late, to the back of the class), and his cataloguing of pitched battles, sorties, skirmishes, naval encounters and assaults on the city, each carefully listed in an appendix. Competing religious enthusiasms are assessed positively and as forces sustaining morale. Concern with modern professional military matters may explain Hosler’s extended yet, despite his claims, unexceptional justification of Richard I’s decision, following the fall of the city, to kill in cold blood perhaps 2,500 to 3,000 of the Muslim garrison troops in his custody in response to Saladin (himself no stranger to the slaughter of POWs) dragging his feet in implementing the city’s surrender terms. It reads like a lawyer’s submission haunted by the spectre of Abu Ghraib.

While occupying far from untrodden historical ground, Hosler’s meticulous study impresses. Although some will find the military detail tedious and, because of the paucity of illuminating maps, hard to follow, if minutiae of battlefield tactics and the experience of combat are your bag, Hosler is definitely for you. Some surprising lacunae appear. There is scant mention of the determining effect of winter mud on military action. While the problems of food supplies are well acknowledged, their provenance is hardly discussed. One puzzle abides. It has been estimated that the crusader army of around 15,000 over the course of the siege required, for men and beasts, 10,000 tons of provisions and 81,000 tons of fresh water. However speculative these figures, with the local hinterland and markets largely in the hands of enemies and, for most of the campaign, ships carrying provisions having to run the gauntlet of Saladin’s fleet, adverse currents and bad weather, the conundrum of supply deserves more attention than it receives.

Similarly cursory treatment is afforded to the organisation of crusader armies: how they were sustained and paid, how allegiances shifted and how lordship and communal groupings developed. Providing generic descriptions of followers misses the protean nature of the crusade host, of which the sources allow intriguing glimpses. Hosler is better at delineating Saladin’s coalition forces and his predicament and perspective. The lack of closer analysis of the crusade’s structure is disappointing given the useful list of participants in an appendix. Fuller consideration of the role of this siege in the development of military technology and tactics would also lend weight to arguments for its historical significance. Without context, the detailed battlefield accounts can appear of mere antiquarian interest. Nonetheless, for the enthusiast and expert alike, Hosler has produced a thorough military description of this major, dramatic confrontation, and it is unlikely to be bettered.