Guglielmo Ratcliff is a tragic opera in four acts by Pietro Mascagni to an Italian libretto by Andrea Maffei, translated from the German play Wilhelm Ratcliff (1822) by Heinrich Heine. Mascagni had substantially finished the composition of Ratcliff before the phenomenal success of his first opera, Cavalleria rusticana.
After the composition and performance of further operas L'amico Fritz in 1891 and I Rantzau in 1893, Ratcliff eventually premiered on 16 February 1895 at the Teatro alla Scala in Milan and has been revived a number of times since, including a concert performance in 2003 at the Alice Tully Hall in New York and a staged performance at Wexford Festival Opera in 2015.
Mascagni often wrote that Ratcliff was his best opera. However, it has not entered the standard operatic repertoire, in part because the title role is one of the most taxing tenor parts ever written. It is especially known for its act 3 Intermezzo, which features prominently in the Martin Scorsese film Raging Bull. (Heine's play was also used as the basis for César Cui's 1869 opera of the same name and for Volkmar Andreae's 1914 opera Ratcliff.)
Count Douglas, Maria's betrothed, arrives at the Castle of Maria and her father MacGregor. He tells them how he was attacked by bandits near the castle but saved by an unknown knight. Maria faints, and then recovers. MacGregor tells Douglas about Gugliemo Ratcliff, whom Maria had rejected as a suitor. Ratcliff's revenge was to challenge her next two suitors to duels in which he killed them. Count Douglas then receives a message from Ratcliff delivered by his friend Lesley challenging him to a similar duel at Black Rock.