The port of Acre lies on a peninsula in the Gulf of Haifa.

East of the old part of the city is the port, protected against the open sea, while to the west and south the coast is protected by a strong dike wall.

The peninsula is guarded on the mainland side by double barrier reinforced with towers.

The Muslim garrison of the city might have been twice as large as the army led by Guy, who arrives on August 28, 1189.

The unscrupulous Guy, despite having taken a vow not to war against Saladin, suddenly gathers his few followers and in a daring move to establish his authority, besieges Acre, taking Saladin completely by surprise.

When he finally moves his army toward the city, the crusaders in their camp outside the walls have begun to receive reinforcements from the West, many under the banner of Henry II, Count of Champagne, the eldest son of Henry I, Count of Champagne and Marie de Champagne, a daughter of King Louis VII of France and Eleanor of Aquitaine.

Joining the Third Crusade alongside both his uncles, King Philip II of France and King Richard I of England, Henry had left for the East after having his barons swear to recognize his younger brother Thibaut as his successor should he fail to return.

He tries to surprise the garrison with an assault on the walls, but this fails and Guy thus establishes his camp outside the city, to wait for reinforcements, which begin to arrive by sea a few days later.

A Danish and Frisian fleet replaces that of the Sicilians, who withdraw when they hear news of the death of William II.

French and Flemish soldiers also arrive under James of Avesnes, Henry I of Bar, Andrew of Brienne, Robert II of Dreux, and his brother Philip of Dreux, the Bishop of Beauvais.

Germans under Margrave Louis III of Thuringia and Otto I of Guelders, and Italians under Archbishop Gerhard of Ravenna and the Bishop of Verona, also arrive.

Louis of Thuringia is able to convince Conrad, his mother's cousin, to send troops from Tyre as well.

When Saladin is informed about this development, he gathers his troops and marches to Acre, where he unsuccessfully attacks Guy’s camp on September 15.

Saladin moves to the east of the city to confront Guy’s camp on October 4, 1189.

The Crusader army (which consists of seven thousand infantry and four hundred cavalry) under Guy stands its ground in front of Saladin’s forces.

The Christian army consists of the feudal lords of the kingdom, many smaller contingents of European Crusaders, and members of the military orders; the Muslim army consists of troops from Egypt, Turkestan, Syria, and Mesopotamia.

The Muslims lie in a semicircle east of the city facing inwards towards Acre.

The Crusader army lies in between, with lightly armed crossbowmen in the first line and the heavy cavalry in second.

At the later Battle of Arsuf the Christians will fight coherently; here, the battle begins with a disjointed combat between the Templars and Saladin's right wing.

The Crusaders are so far successful that the enemy has to send reinforcements from other parts of the field.

Thus, the steady advance of the Christian center against Saladin's own corps, in which the crossbows prepare the way for the charge of the men-at-arms, meets with no great resistance.

Saladin’s center and right flanks are put to flight, but the victors scatter to plunder.

Saladin rallies his men, and, when the Christians begin to retire with their booty, lets loose his light cavalry upon them.

No connected resistance is offered, and the Turks slaughter the fugitives until checked by the fresh troops of the Christian right flank.

Into this fight, Guy's reserves, charged with holding back the Saracens in Acre, are also drawn, and, thus freed, five thousand men sally out from the town to the northward; uniting with the Saracen right wing, they fall upon the Templars, who suffer severely in their retreat.

Gerard de Ridefort, Grand Master of the Templars, is killed.

Andrew of Brienne is also killed and Conrad has to be rescued by Guy.

In the end, the Crusaders repulse the relieving army.

Saladin cannot push them back without another pitched battle, and his victory remains incomplete.

More European Crusaders had arrived during the autumn, allowing Guy to blockade Acre by land.

News of the imminent arrival of Emperor Frederick Barbarossa reaches the Crusaders, which not only raises the morale of the Christian soldiers, but also compels Saladin to bring in so many more troops that he is able to surround both the city and the Crusade camp in two separate sieges.

Fifty Muslim galleys break through the Christian sea blockade on October 31 and supply the city with food and weapons.

An Egyptian fleet arrives on December 26 to reestablish control over the port and the road leading to it.

Conrad travels to Tyre on his own ship on March 1190, when the weather is better, and soon returns with supplies for the Crusaders, which helps the resistance against the Egyptian fleet on the shore.

The building materials brought by Conrad are constructed into siege machinery, although these machines are lost when the Crusaders try to assault the city on May 5.

Saladin, who has continued to strengthen his army over the previous months, on May 19 begins an attack on the Christian camp, which lasts eight days before it can be repelled.

The Christian soldiers, against the orders of their commanders, attack Saladin’s right flank on July 25 and are defeated.

Further reinforcements from France arrive in the Crusader camp over the summer, led by Henry II of Champagne, Theobald V of Blois, Stephen I of Sancerre, Ralph of Clermont, John of Fontigny, Alain of Saint-Valéry, the Archbishop of Besançon, the Bishop of Blois, and the Bishop of Toul.

Life in the city and the Christian camp quickly became difficult after their containment by Saladin.

Food remains limited, the water supply had become contaminated with human and animal corpses, and epidemics soon began to spread.

Louis of Thuringia, sick with malaria, makes plans to return home when the French arrived; he will die in Cyprus on the way back on October 16.

Among the victims of disease is Guy's wife, Sibylla, the source of his own claims to the throne, a few days after both of their daughters, Alais and Marie.

Sibylla’s rightful heir is her younger half-sister, Isabella of Jerusalem.

Frederick of Swabia arrives at the beginning of October with only the small remnant of Barbarossa’s army had finally reached Tyre after the emperor had drowned in the Saleph River on June 10.

To Saladin and the Muslims, who had been seriously alarmed by the approach of Frederick Barbarossa, the German emperor's death seems an act of God.

English Crusaders arrive shortly afterwards under Baldwin of Exeter, Archbishop of Canterbury.

The Count of Bar arrives in October and the Christians have a breakthrough in Haifa, which allows more food to be brought to the camp at Acre.