Queen Maud is depicted inside Lincoln Castle during the battle of February 1141. In fact she was in Gloucester, over a hundred miles away.
Robert of Gloucester was not captured at the Battle of Lincoln at the same time as King Stephen, as shown. Rather, it was Gloucester who took the king into custody. Gloucester's capture happened seven months later, in September 1141, at the Rout of Winchester.
Regan Hamleigh refers to young Henry as Maud's only son. In actual fact, Maud gave birth to three sons named Henry, Geoffrey and William.
Maud is shown suddenly deciding to take on the title of Empress on a whim. In truth, she carried the title because she had been briefly married as a young girl to the Holy Roman Emperor.
Shiring Castle is shown as a structure from the Tudor/Elizabethan era, 400 years in the future.