Acre did not prove easy to conquer, and Guy's assault quickly evolved into a protracted siege. Hearing news of this attack, Saladin promptly gathered a relief force for the rescue of Acre. Meanwhile, newly arriving Crusaders from across the seas rallied to Guy's initiative, even convincing Conrad to do the same with his army of Tyre.
On 4 October, Saladin's army clashed with the besiegers who were trapped between the Saracens of the city and the relief force. In spite of this, the Saracens failed to dislodge the invaders from their position. They did, however, manage to capture Gerard de Ridefort once again. Refusing to repeat his previous act of mercy, Saladin executed the Templar Grand Master by decapitation.
After this intense battle, both sides settled into their respective blockades. While the Crusaders resumed their investment of Acre, the relief force kept the Crusaders surrounded with no hope of escape. Throughout the next year, reinforcements continued to arrive from various states in Europe to assist the siege, such as the remnants of the Holy Roman Empire army led by Frederick VI of Swabia whose father, the Emperor Frederick Barbarossa, had drowned en route to the Levant.
In response, the Saracens continued to call in reinforcements of their own, and the number of soldiers involved in the siege massively swelled. Eventually, both the city and the Christian camp were entirely contained by Saladin's forces, a state of affairs that severely impacted the living conditions for the Crusaders. Epidemics broke out and even the Crusader leaders began to succumb to disease, including Duke Frederick VI of Swabia.
- “...there's a plan to poison every water source in the city. Everyone will die. The city will be empty before sunrise.”
- ―Basilisk revealing the poison plot to Altaïr, 1190[来源]
Sometime in that same year, 1190, the Templars, frustrated with the stalemate, hatched a secret scheme to poison the entire water supply of Acre. Such was the extent of the operation that they expected the entire population of the city to die by the next morning, leaving the city empty for the Crusaders' taking.
When the de facto successor to Gerard, Basilisk, was defeated by the Assassin Altaïr Ibn-La'Ahad in Tyre, however, the Templar leaked the plot to the Assassin in exchange for mercy. As both were in a competition for the Chalice, which they now knew to be a woman hiding in Jerusalem, Basilisk hoped that by playing on Altaïr's conscience to save Acre, he would delay the Assassin long enough for him to reach Jerusalem first.
Sure enough, Altaïr detoured to Acre, desperate to rescue its people from the massacre that could be carried out at anytime. The night of his arrival in the city, the Crusaders' latest assault had finally breached sections of the city wall, allowing some of their forces to surge through.
When three Hosptalier soldiers spotted Altaïr, he evaded them by throwing a smoke bomb and fleeing to the rooftops, from where he then sniped a few Templars with a crossbow. His indiscretion alerted the invaders of his presence, and Crusaders entering into the city were on the look out for him. As soon as he returned to the streets, he was confronted by a group of Crusaders who were immediately killed by a collapsing building. Rather than offering a reprieve, the commotion attracted the attention of more soldiers who Altaïr swiftly dispatched.
Altaïr intended to travel to the other side of the city to reach the Templar camp and assassinate the general in charge of the poison plot. After killing more Crusaders along the way, he found his route down a street blocked by a Templar commander and three of his knights. While his knights barricaded the way with their shields, the commander eagerly drew his sword at the Assassin, only to be slain in the ensuing duel. His knights nevertheless maintained their shield barricade, only to have Altaïr forcibly break through it and escape.
Moving on, the Assassin found himself before a city gate just as it was blasted open by the Crusaders, killing the Saracens that were desperately holding it back. Altaïr alone held back the force of Crusaders pouring in through the gate, but after a while, he came to realize the futility of this. Thinking quickly, he launched a catapult to destroy the lintel of the gate: the collapsing debris sealed the breach, forcing the Crusaders outside to scale the wall with ladders.
To this, Altaïr responded by firing ballistae from the walls at Crusaders on observation towers as well as pushing down any ladders raised. His actions successfully stalled the assault on that section, and he proceeded onward to a square nearby where Templars were assembling civilians for execution. From his vantage point on the roofs, the Assassin sniped the executioner with his crossbow before killing the rest of his compatriots.
As he battled the invaders through the streets and rooftops, he rescued another woman who was taken prisoner by Hospitalier soldiers. At last he reached the gate closest to the Templar camp, one that had also been breached but with Saracens still defending it. While Altaïr repeated his solution before: using a catapult to destroy the lintel to seal the breach, the Saracens mistook him for an enemy, recognizing him to be an Assassin.
Knowing that he could not exit the city through the gate itself without attracting enemies, Altaïr escaped the Saracens and fled onto the wall, from where he was able to then stealthily lower himself to the other side via a ladder while the combatants were preoccupied with the battle.
Arriving at the Templar camp, Altaïr was accosted by two sergeants that demanded he relinquish all his weapons as per orders to disarm all civilians. To this, the Assassin consented, retaining only his Hidden Blade, but the guards forbade his entry. Without waiting to see if their would-be trespasser complied, they left him to return to their posts. Altaïr thus found himself free to sneak up on an unsuspecting soldier, kill him, and retrieve his uniform to serve as a disguise.
The disguise proved effective, allowing him to explore the camp unmolested until he reached an area walled off by palisades. The guards at the gate prohibited Altaïr from passing through the checkpoint, reminding him that a soldier of his rank was not allowed inside, not realizing his true identity. Opting to create a diversion, the Assassin detonated explosives he found at a section of the camp. With many tents ablaze and the flames rapidly spreading, the guards before the gate felt compelled to leave their post to assist in extinguishing the fire.
It was this point that Altaïr slipped inside. Well aware that his disguise would not be effective in this area, the Assassin was forced to rely purely on his skill at stealth to elude detection. When he came across a trebuchet, he decided to tamper with it to create yet another diversion. As he expected, a couple of soldiers noticed the malfunction and attempted to repair it, only to trigger a trap that caused the machine to drop its flaming projectile onto them. The "accident" lured more soldiers over to investigate, alleviating pressure for Altaïr to move forward.
Approaching another wooden wall, Altaïr took note that scholars were permitted to move freely through this next checkpoint, correctly assuming that only captains were granted entry otherwise. He therefore killed a scholar idling in solitude and changed into his robes, allowing him to enter through the gate by blending in with a group of scholars.
Within this section of the camp, the Assassin assassinated the knights guarding a group of ballistae before destroying the weapons with explosives. While alarmed knights rushed to the scene of the disaster, he traveled deeper into the camp until he was stopped by another knight who informed him that scholars were prohibited from proceeding any further. This knight was secretly conspiring to liberate a young woman imprisoned by the Templars and bargained to allow Altaïr through if he were to steal the key to the prisoner's cage from the torturer. The Assassins accomplished this without issue, and the grateful knight freed the girl and hastily left to escort her out of the camp.
Nevertheless, Altaïr had not advanced much further before he reached the gate of a final enclosure, where only captains were granted entry. Seeking an opportunity to foment another diversion, he sneaked into a nearby large tent and discovered that it was a detention center for prisoners-of-war. One such prisoner was in the midst of being tortured by a Templar for the whereabouts of a great treasure. Without further ado, Altaïr ended the interrogation by assassinating the torturer from behind. In gratitude, the Saracen tried to reveal the location of the treasure to the Assassin but succumbed to his wounds before he was able to complete his sentence. Only mildly disappointed, Altaïr then liberated all the other prisoners, counting on the prison break to lure the guards away.
Indeed, the two captains guarding the last checkpoint rushed off in pursuit of the escaping prisoners, and Altaïr proceeded inside. Soon he came upon a line of trebuchets being operated against the city. Keen as he was on stopping them—even at risk of blowing his cover—he killed a crossbowman overlooking the trebuchets on a lookout tower, then recovered the crossbow to use against the soldiers operating the siege weapons. After sniping two of them, the rest of the group looked up to find the source of the attack but were too stunned to react before they were all shot down.
- Commander：“Scholar, this is it! I sense that our victory is at hand!”
- Altaïr：“You couldn't be more... Mistaken!”
- ―Altaïr preparing to assassinate the Templar commander, 1190[来源]
Up ahead before him was the base of the Templar commander in charge of the operation to poison the city. Though he had yet delivered the order for the poisoning of the city, Altaïr had reason to believe that it would occur that very night. It just so happened that as he neared the gate of the base, the commander issued a summons for all his captains to meet with him for an announcement. The captain that came out to call on all the other captains was the only one who stayed behind to guard the entrance while the rest hurried inside for the speech. As a result, Altaïr had no trouble sneaking through the gate, in time to witness the commander rallying his captains to prepare for an all-out assault against Acre.
The commander had preemptively assumed that the city's defenses had been all but annihilated—a conclusion that was incorrect—and he had refrained from issuing the command for the poisoning before dismissing his captains. As the captains departed from the meeting, the commander spotted Altaïr lurking about. Believing him to be a mere scholar, and excusing the fact he had trespassed well beyond the boundaries for scholars, he requested Altaïr to join him and give him his blessings from God. Thus, the Assassin climbed up onto the roof of the small, ruined building from which the commander had delivered his speech.
Watching the battle over the city from afar, the Templar commander proclaimed his imminent victory. With his back turned to Altaïr, the Assassin seized a sword and prepared to strike him down. However, his indiscretion—neglecting the Hidden Blade and shouting that the Templar was mistaken beforehand—gave the commander the chance to wheel around with his own sword drawn and defend himself. The commander wasted no time in calling for his guards who raised the alarm.
As Altaïr and the commander clashed on top of the small roof, Templar soldiers rushed to assist their leader. Because they required the ladders to climb onto the roof, they could not swarm the Assassin all at once, ensuring that he was only outnumbered by several solders at any given time. A master swordsman, Altaïr had no trouble holding his own in spite of the disadvantage, slaying any Templar that made it to the roof to join their commander, and eventually overwhelming the leader himself and disarming him. Shocked and wounded, the Templar commander could do little as Altaïr swiftly followed through by pouncing to execute him with his Hidden Blade.
Although victorious, the Assassin now realized that he was deep in the center of an enemy camp on high alert for his whereabouts. Despite his skills, he did not entertain the possibility that he could fight his way through the entire army out and frantically searched for an exit. It was then that he looked to a nearby catapult for his escape. In as desperate of a predicament he was, he did not hesitate to climb onto its bucket and launch himself towards the city of Acre just as Templar knights charged at him from behind believing him caught for good.
Altaïr survived his stunt, and content with having foiled the poison plot by assassinating the commander in charge of its order, he hurried to Jerusalem to find the mysterious woman that was the Chalice. Fortunately for him, his decision to burn Basilisk's fleet in Tyre before making his journey to Acre would ensure that the Templars would only beat him to the target by mere moments.
Altaïr Ibn-La'Ahad's intervention, while not crippling it outright, did disrupt the Crusaders' siege. The night he killed one of the leading Templar commanders, the Templars had expected that their invasion would prove victorious by the morning, given that multiple breaches had already been blasted through the walls, and droves of Crusaders had already found their way inside the city. Much to their chagrin, by the next day, the Crusaders had in fact been driven back from Acre. The walls were reinforced and fortifications restored; the Saracens and Crusaders were once again at an impasse, one that would drag on for yet another year, facilitated in part by the destruction of some of the siege weapons.
Throughout that time, the Crusader camp continued to be afflicted by disease, propagated by their own contaminated water supply. The epidemic claimed the lives of many Christian leaders, among them Queen Sibylla herself, whose death voided Guy of Lusignan's legal claim to the throne of Jerusalem, though he refused to surrender it.
Not until April of 1191 did the long awaited army of France led by King Philip Augustus arrive, to be followed by England under King Richard the Lionheart in June. Richard had been delayed by a conquest of Cyprus, which he would immediately sell to the Knights Templar, but upon their rendezvous at Acre, the tide swiftly turned against the Saracens. With the supplies to build more siege weapons, breaches within Acre's walls became more and more frequent, but Saladin continued to be prompt in assaulting the Crusaders from behind to deter them whenever they sought to exploit these openings. In spite of this, the Acre garrison came to recognize a worsening situation and lost the morale to maintain their defense any longer. On 12 July, the city surrendered conditionally, with their terms accepted by the Crusaders. Saladin, whose army still largely blockaded the Crusaders respected the capitulation.
When the Crusaders entered Acre, they immediately seized three thousand of its population to use as bargain for the Christian prisoners in the Saracens' hands. Erstwhile, Conrad of Montferrat, insistent on the kingship of Jerusalem, had married Isabella, the half-sister of Sibylla and the rightful heir to the throne since Sibylla's death. His contest for the Jerusalemite throne in opposition to Guy of Lusignan angered King Richard, for Guy was his vassal. Despite this, the English king appointed Conrad's father Marquis William V of Montferrat as his regent in Acre.
Philip Augustus of France did not linger long after the fall of Acre. By the end of the month, he aborted his participation in the crusade to return home to moderate the succession over the Counties of Flander and Vermandois, which he feared would be in dispute after their count Philip of Alsace perished to the epidemic at the siege. His departure left Richard in overall command of the entire Crusader force.
Negotiations between Richard and Saladin—of which Conrad served as a chief negotiator—lasted until 20 August. Against Richard's own judgment, William had all three thousand Muslim hostages decapitated before the eyes of Saladin's army. In retaliation, Saladin returned the favor, executing every last Christian prisoner his army held. In the wake of this violent breakdown in diplomacy, Conrad stormed back to Tyre, and it was speculated by the Assassin Rafiq Jabal that William appointment as regent was in fact Richard's way of keeping him hostage to discourage Conrad from betraying him.
Once it was clear that the war would resume, Richard led his forces out from Acre to Jaffa, a port city whose control was vital for the Crusaders to have a chance of retaking Jerusalem. For the next weeks, his army would be pursued by Saladin's forces, whose camel archers and raiders would dog his march for the entire way until Saladin finally intercepted Richard at Arsuf on 7 September, the site of the next major battle of the Third Crusade. The Crusaders' decisive victory there would open their way for another victory at Jaffa and the path to Jerusalem though the war would end without them ever attacking it as a result of internal dissent.