Tasso, Lamento e Trionfo ( Tasso, Lament and Triumph) was inspired by the life of Torquato Tasso, an Italian poet of the 16th century. Liszt referred to two works written about the poet, one by German writer and poet Johann von Goethe and another by Lord Byron, an English poet. Tasso suffered from mental illness and spent many years in an asylum. He did eventually leave the asylum and resumed his writing, but he was never cured. It is now thought that he suffered from schizophrenia.
It was the sufferings and inner turmoil of Tasso's years spent in the asylum that Liszt depicts in music in the first half of the piece, with the triumph and release from the asylum and the resumption of his creative work that is depicted in the second half.
Liszt wrote 13 of these one movement Tone Poems, with Tasso being number two. They were all inspired by literature, art, or some other non-musical source. With this series of Tone Poems, Liszt created a new type of composition, one well suited to the Romantic era of the 19th century.