Isfahan is supposedly attacked by Seljuq (not to be confused with Seleucids) forces under the command of Tugrul Bey in the final days of Ibn Sina, 1037. But that year, Bey sacked Ghazni instead, some 1575 Kilometers away. Seljuk empire did not conquer Isfahan and made it its capital until 1051.
Rebecca tells a sick girl the story of Aladdin from what seems to be a pocket version of the 1001 Nights. She added that Sinbad was her favorite tale from the book. Besides it being improbable that such a book format existed then, "Aladdin's Wonderful Lamp", "Ali Baba and the Forty Thieves" and "The Seven Voyages of Sinbad the Sailor", while almost certainly genuine Middle Eastern folk tales, were not part of The 1001 Nights in Arabic versions, but were added into the collection by Antoine Galland and other European translators in the 17th century.
The Farsi (Persian language) being spoken by the commoners and extras throughout the movie is modern day *Hebrew*, which wasn't spoken by Jews or Persians and has only been revived as the language of Jewish people in Israel beginning the late 1800s.
The main character, an Englishman born in the early 11th century, is named Robert Cole. But names like 'Robert' which are of French origin really came to be used in England only after 1066 i.e. the year of the conquest of England by the Normans. Until then, parents chose Anglo-Saxon names for their boys like Wybert, Alfred, Edgar and Harold.
Last years of Ibn Sina (Avicenna) were spent in the service of the Kakuyid ruler Muhammad ibn Rustam Dushmanziyar, also known by his surname Ala al-Dawla Muhammad. Muhammad was not defeated by Seljuq forces, but began constructing instead massive defensive walls around Isfahan which later saved it from these Turkmen nomads who sacked and plundered some places in west and central Iran in 1038/39, including the city of Hamadan.
It is assumed that human dissection was forbidden by the Shareeah in the middle age, so both Ibn Sina and Rob Cole are sentenced to death by an Islamic court. In fact, systematic dissections of the human body were performed neither in Islam nor in England not only due to religious prohibitions, but also because they were considered unnecessary, although they would be done occasionally. Today, dissecting humans is allowed in Islam and in Christian lands under certain circumstances.
The Tefillin or phylacteries (black boxes) that the Jews bind to themselves are not shown being bound in the proper order. They are wearing the tefillin on their head before binding the tefillin to the arm. Additionally Jews never pray while kneeling.
The movie begins in 1031 when Rob is 10 and goes, at most, 25 years into the future, say, to 1056. As a result, the final shot revealing the Tower of London amid mud huts would still be quite a bit in the future considering that William didn't build it until after the Conquest of 1066.
Rob is shown cutting ice from a block to place on Rebecca's head. There is no location from where the ice could have come that would have been easily available to the population (if at all). It would have taken a tremendous amount of ice, well insulated, in order to have survived any proposed journey from a snow covered mountain anywhere in the region. While there are snow covered mountains in the region (depending on time of year and geography), a solid ice block as depicted in the movie would have needed to be pulled from a glacier (or frozen lake/stream) which do not exist in the region.
In the final scene on the battlefield when Isfahan is attacked by the Sentjoeks, one of the actors who plays a dead soldier takes a very quick look at the Shah just before the camera stops to focus on him.
The goof item below may give away important plot points.
Ibn Sina didn't commit suicide in Isfahan, he died of illness in Hamadan.
His friends advised him to slow down and take life moderately. He refused, however, stating that: "I prefer a short life with width to a narrow one with length".
He died in June 1037, in his fifty-eighth year, in the month of Ramadan and was buried in Hamadan, Iran.