Anjelica Huston was able to keep several of the dresses used in the film and several women wore them during the Baptism of Anjelica's nephew Rafa (the son of her sister Allegra).
Elaine tells Gwhenhwyfar she is the "happiest girl in England". The film is set in the sixth century, but the country was not known as England until around the dawn of the 11th century. Elaine would have referred to the land as Britain or the Roman form, Brittania.
In the scene where Gwenhwyfar and Lancelot kiss in the chapel, the cross on the altar is draped with a rosary. The film is set in the fifth century, but the rosary did not exist until the early 13th century.
Gwenhwyfar: You say you are a good man, but you condemn your wife to barrenness for the sake of an oath to painted savages. I despise you, Arthur Pendragon! Neither good Christian, nor good pagan, nor a good husband to me.