Complex sentence: The interior was decorated with fine frescoes initially by Gualtiero Padovano, and later by Giovanni Battista Zelotti and Battista del Moro in whose "Hall of the Muses" are to be seen caryatids within a composition of muses and poets in Arcadian landscapes.
Split into simpler sentences: The interior was decorated with frescoes initially by Gualtiero Padovano, and later by Giovanni Battista Zelotti and Battista del Moro. Their "Hall of the Muses" includes depictions of caryatids within a composition of muses and poets in Arcadian landscapes.