Horses are shod with modern nailed horseshoes. The most probable horseshoes at the time of Alexander should have been leather and plants "booties" of Asian origin. In the 1st century, Romans used leather and iron "hipposandals". Nailed iron horseshoes seem to have become adopted much later.
Knick knacks in Olympia's boudoir include the Sumerian Goat and Tree excavated at Ur, in modern day Iraq, by Leonard Woolley in 1927. Created and buried more than 2000 years before Alexander was born, it's unlikely his Mum had one on her sideboard.
In the Final Cut, when Alexander is giving his speech to his men at Gaugemela. The officer who hands him his helmet is on his right, but in the next scene he is on his left handing Alexander his helmet.
In the final battle, before Alexander would ride towards the elephant, he is seen holding a spear, even waving it and pointing with it to his men to move forward. One second later he is carrying a sword, with the spear nowhere to be seen.
When Aristotle is describing what he thinks might be a route to circle around to the headwaters of the Nile and travel down it to conquer Egypt, he refers to going "up the Nile," rather than down it. This may be due to the modern map convention of showing North at the top of maps and referring to traveling in a northerly direction as going "up". The Nile River flows from South to North and thus traveling down the river is going North.
Alexander asks Darius' daughter how she wishes to be treated, she replies, "like a princess," and he grants her wish. In reality, Alexander asked the question to the Indian king Porus. When Porus replied "like a king", he won Alexander's respect and became one of his allies.
Philotas is depicted as fighting on foot alongside his father on the Macedonian left flank at Gaugamela. Philotas was always recorded as riding with the Companion Cavalry. However, his arrogant disposition and tendency to draw unwanted attention to himself are accurately portrayed, particularly in the Revisited Cut.
When the men mutiny at the river Beas, Craterus speaks of 'these elephant monsters' implying that the Macedonians have only heard of them. This is ridiculous, because not only had they already fought the battle of Hydaspes (depicted in the film as after the mutiny), but they also would have seen the elephants at Gaugamela (Darius had brought a few elephants to the battle, but they saw little action).
On the map of the known world, the Black Sea is correctly called "Pontos Euxeinos," but the Mediterranean is called "Mare Mediterraneum." On Roman maps, it was called "Mare Nostrum" (Our Sea) or "Mare Internum" (Inner Sea). In the fifth century BC, Herodotos called it the "Pontos Boreios" (Northern Sea).
In the film, the final battle against the Indians is depicted as taking place in a jungle, whereas in reality the battle - known as the Battle of the Hydaspes - took place on the banks of the river Hydaspses (now known as the Jhelum).
On road marches (as opposed to marching to contact, i.e., when the enemy is in sight or there is imminent contact), the 4 to 7 metre (13 to 21 feet) sarissa would have been broken down into its two components for ease of transport. In the movie, the sarissa is always shown at full length deployment.
There are some English texts to be seen throughout the movie. When young Alexander is taught about the world as it has been explored in these ancient times, the teacher stands on a mosaic showing the countries' and regions' names in English. Another appearance of the English language happens on a report lying on Alexander's desk, titled "TAX SYSTEM" in fake Greek letters.
During the battle in India, the infantry are shown fighting in phalanx formation with the long spears (known as sarissas). However, according to such historians as Robin Lane Fox, they had given up fighting with the sarissa by the time they reached India.
Many scenes were re-ordered in the "Final Cut." For example, Alexander's childhood is seen in flashback, not at the beginning, in chronological order. However, the end credits are the same, so the list of actors "in order of appearance" is inaccurate.
When it comes to naming an heir to Alexander's empire on his deathbed, no mention is made of Alexander's half-brother, Philip Arrhidaeus. Despite his noted learning disability, Arrhidaeus was held up as the true Macedonian heir to Alexander's empire by many men in the Macedonian army (Alexander's child by Roxane was still unborn before Alexander died and was also half-Iranian, which fueled Hellenic prejudices). Arrhidaeus was crowned Philip III after Alexander's death as co-ruler alongside Alexander's unborn child (who became Alexander IV). While some have called the film out on this factual error, the omission was clearly done to compress the story of Alexander into a single film.
[Director's Final Cut] At Philip's wedding, when Attalus is toasting a Macedonian Queen to be proud of, he pauses to glare at Alexander but as he does so, his dialog continues without moving his mouth. This, however, is an intentional artistic flourish that is typical of Oliver Stone's films.
Although Cassander is a main character, and leads the cavalry under Alexander at Gaugamela and Hydaspes, his actual role in history is much smaller. He is first recorded in the year that Alexander died, sent by his father to Babylon. This gave rise to the idea that he came with poison that eventually killed Alexander.
Olympias, Ptolemy, Parmenion, and Attalus are all witnesses to Philip's murder, while Nearchus is among the men who pursue Pausanias, murderer of Philip, and then spear him to death. However, none of them would have been present at Philip's murder. Olympias, Nearchus, and Ptolemy were all in exile from Macedonia and only returned when Alexander was crowned king, while Parmenion and Attalus were abroad in western Asia, to pave the way for Philip's planned invasion.
After Alexander tells his army that they'll leave India and march home to Babylon, Ptolemy narrates that Alexander marched his army "directly west across the great Gedrosian desert, seeking the shortest route home to Babylon". This is somewhat inaccurate. While Alexander did march part of his army through the Gedrosian desert (the fleet and the veterans were spared the march), it certainly wasn't the shortest route home to Babylon. In fact, going through the Gedrosian desert was by far the most dangerous route possible and certainly not the shortest route. The only reason Alexander decided to march through the desert was for his own glory, because no other army had ever crossed the desert alive, and he wanted to be the first to hold the honour of doing so.
Alexander is depicted as holding out his ring straight into the air before dying, whereupon the ring falls to the ground and collapses. This goes against records which claim that Alexander gave his ring to Perdiccas. While depicted as a fairly minor character, Perdiccas played a large role in the campaigns of Alexander. He assumed command of the Companion Cavalry when Hephaistion died, and by receiving Alexander's ring, he was the assumed regent of Alexander's empire until his son would come of age.
It is implied during the battle in India that Antigonus has a command over the Shield Bearers, an elite division in the Macedonian army. This was not so. For that matter, Antigonus would not have been in India at all, as he was the satrap of Phrygia at the time. He would only really rise to prominence after Alexander's death, much like Cassander.
As Alexander comforts a dying Hephaistion, he tells him that they'll set sail from Babylon and conquer various peoples and lands, one of them being "the Roman tribe" as Alexander describes them. Being a well-educated man, Alexander should have known that the Romans were not just a mere "tribe", but were a fully functioning republic by 323 BC (when this scene took place).