Who was Archduchess Maria Anna of Austria's grandfather on her mothers side?
Maria Theresa of Naples and Sicily: Maria Theresa of Naples and Sicily (6 June 1772 – 13 April 1807) was the last Holy Roman Empress and the first Empress of Austria by marriage to Francis II, Holy Roman Emperor. Maria Theresa of Naples and Sicily:  She was the eldest daughter of Ferdinand IV & III of Naples and Sicily (later Ferdinand I of the Two Sicilies) (1751–1825) and his wife, Marie Caroline of Austria (1752–1814).
i don't know