- "We'll see how sweet they are, the fruits of your labors. You do not free the cities as you believe, but rather damn them. And in the end, you'll have only yourself to blame. You, who speak of good intentions."
- ―William of Montferrat in his final moments, 1191.[src]
Guglielmo V Aleramici, Marchese del Monferrato (1136 – 1191), often anglicized as William of Montferrat, was a Crusader in the army of King Richard I of England, Marquess of Montferrat and, secretly, a member of the Knights Templar.
Following Acre's conquest, Montferrat became the regent of the city, and as a result of Al Mualim's plan to free the Kingdom of conflict, he became the fifth target of the Levantine Assassin Altaïr Ibn-La'Ahad.
Regent of Acre
- "The city belongs to its people."
- ―William of Montferrat[src]
At some point during his life, William joined the Christian monastic-military order known as the Knights Templar. Despite the Order's public service of protecting pilgrims on the road to the Holy Land, William became involved in the Grand Master Robert de Sablé's plot to usurp control of the Holy Land from both the warring Christians and Saracens. To this end, William became involved in Robert's plan to obtain the legendary Apple of Eden.
In the aftermath of the fall of Acre, William was appointed as the city's regent by King Richard the Lionheart. Though this was ostensibly a show of trust by Richard, the Assassin Rafiq Jabal deduced that it was in fact a way to keep William a hostage to deter any act of rebellion by his son Conrad. Since Conrad vied for the kingship of Jerusalem against Guy of Lusignan, a vassal of Richard, Richard bore much enmity for him. Contrary to popular belief, William himself held little respect for his son, yet his relationship with the king was stained with mutual distrust. It became a frequent habit of William to take his frustration out on his soldiers after being scolded by the king.
On 20 August 1191, believing that this would instill fear on the Saracens, William authorized the execution of 3,000 Saracen prisoners whom King Richard had planned to trade for Christians likewise captured by Sultan Saladin of Egypt. However, for this deed, William was publicly denounced by the King of England, who rightly predicted that it would strengthen the enemy's resolve instead.
Erstwhile, his membership in Robert's scheme became known to the Assassins of Masyaf—sworn enemies of the Knights Templar—and so he was chosen to be eliminated. On the orders of Al Mualim, Altaïr Ibn-La'Ahad arrived in Acre to begin his investigation into William's life, and he soon discovered that William was withholding food and money from the citizens. Alongside this, the Assassin learned of the ever-growing divide between Richard I and his regent.
After gathering enough intel, Altaïr made his way to the front of the King's citadel, where he witnessed Richard and William's argument over the Saracen executions. During this conversation, William complained that the King had judged him too quickly, and that he did not trust him enough. Outraged, King Richard responded that he had left William as Acre's regent, an honor which should not have been underestimated. With this, William railed that the king had missed his point entirely, but Richard abruptly ended their quarrel, finding it a waste of time in the face of a war.
Angered by the shame of being publicly reprimanded, William returned to the citadel, where he took his temper out on his men as usual. In a corner of the keep, William began to berate his soldiers, accusing them all of dereliction of duties, and intending to motivate them towards greater discipline and diligence. He ordered that from that day forth, their training would double in intensity, even at the cost of rest and nourishment. To enforce his point, he brought forth two men who had been neglectful of their duties while on patrol, then had their throats slit to serve as an example to the rest.
Altaïr, who had followed William into the fortress, silently and skillfully eliminated the archers around the fortifications' perimeter. When William concluded his latest lecture, his forces left, and he began to look through his papers. It was during this time that Altaïr leapt down and assassinated William with his Hidden Blade.
As William laid mortally injured, Altaïr remarked that he knew William plotted to murder King Richard to give the city to his son Conrad—a claim that William caustically denied. Much to the Assassin's shock, William countered that he felt Acre neither belonged to Richard nor his son, but rather to its people. He asserted that he had only been upholding order, and that he had not been stealing resources from the citizens, but was simply stockpiling them to be distributed efficiently in times of hardship. Even so, Altaïr insisted that William's deeds were nothing but cruel, to which William used his dying words to accuse his killer of condemning cities to adversity rather than saving them. Before Altaïr could argue any further, William perished, and the Assassin made his escape from the fortress.
Personality and characteristics
Although not a giant of a man, William of Montferrat was nevertheless set in the belief that might makes right, and he spent countless hours training and berating his men, to prepare them for the "coming war." Oddly enough, few of his soldiers had actually joined King Richard's march to the Arsuf plains, leading people to wonder about what "war" he spoke about. 
As a strict taskmaster and disciplinarian, William constantly demanded perfection from his men, and was both quick to point out flaws and reluctant to give praise. He was often witnessed shouting, and rarely seemed happy. Later, when two of his soldiers were caught whoring and drinking while on duty, he killed them as an example for the rest of his men.
- The choice of William as a target for Altaïr was inspired by the fact that, historically, his son Conrad, King of Jerusalem, was murdered by the Assassins in Acre in 1192. In reality, William was an elderly man during the events of the Third Crusade and he was called William the Old to distinguish himself to his other son, William Longsword.
- Assassin's Creed producer Jade Raymond revealed that they had originally planned to have Conrad of Montferrat in the game. Their research indicated that he wasn't killed in 1191, but William, Conrad's father, was located in Acre in the same period. In order to maintain the historical accuracy of the project, William was inserted into the game in his stead.
- Though he was actually Italian (Piedmontese) in real life, the William in the game speaks with a perfect English accent.
- In the novel, William is erroneously referred to as being French.
- During the argument between Richard and William, the king blames William for the execution of Saracen prisoners, referring to the event known as the Massacre at Ayyadieh. Quite ironically however, historically it was Richard who had ordered the act.
- The apparition of William conjured by Al Mualim during Al Mualim's fight with Altaïr sometimes shouts orders to his men that they should lure Altaïr to nearby archers.
- A glitch can occur in Assassin's Creed if William pursued Altaïr to the upper walls of citadel. From there, it would be possible to climb on top of the battlements and push him off into the sea below. A message would then announce the failure of the mission since the target had "escaped."
- In the mobile version of Assassin's Creed, William is the second target of Altaïr. Unlike in the console version, he is air assassinated by Altaïr while riding on a horse alongside his lancers, and the Assassin then proceeds to hijack his galloping horse to escape.