Song “Over the Rainbow” vs. Mascagni’s Opera Guglielmo Ratcliff (Intermezzo) – A Case of “Plagiarism”?

Everyone knows the main melody of the Intermezzo (Ratcliff’s Dream) from Mascagni’s opera Guglielmo Ratcliff (1895) even if they have never heard of this opera or the composer before, and this is because it is very similar to the song we all know – “Over the Rainbow”, composed by Harold Arlen for the classic film The Wizard of Oz (1939). I have always been interested in music/film similarities, and possible plagiarism claims, and have decided to investigate this further in this ranty post. To begin with, certain facts do not sit well with me. On the one hand, we have a quite obscure Italian opera and, on the other, one of the most iconic film tunes of all time. Guglielmo Ratcliff is rarely performed, not least because of its voicing difficulty, and it was also overshadowed by the composer’s own work, opera Cavalleria Rusticana, meaning that an average person (especially outside of Italy) would likely not know of it. The Intermezzo was later used in Scorsese’s Raging Bull (1980), but this occurred about 40 years after the legacy of “Over the Rainbow” had already been cemented. Another interesting fact is that, in essence, Harold Arlen is known for “Over the Rainbow”. He was a prolif...