Context : La donna del lago (The Lady of the Lake) is an opera composed by Gioachino Rossini with a libretto by Andrea Leone Tottola (whose verses are described as ``limpid'' by one critic) based on the French translation of The Lady of the Lake, a narrative poem written in 1810 by Sir Walter Scott, whose work continued to popularize the image of the romantic highlands. 
Question : The La donna del lago is based upon what?
The Lady of the Lake