How many operas make up Wagner's Ring cycle?

Wilhelm Richard Wagner (22 May 1813 – 13 February 1883) was a German composer, theatre director, polemicist, and conductor who is chiefly known for his operas.

'Der Ring des Nibelungen' (The Ring of the Nibelung), is a cycle of four German-language epic music dramas composed by Richard Wagner. The works are based loosely on characters from Norse sagas and the 'Nibelungenlied' (an epic poem written around 1200). The composer termed the cycle a 'Bühnenfestspiel' (stage festival play), structured in three days preceded by a 'Vorabend' (preliminary evening). It is often referred to as the 'Ring cycle', 'Wagner's Ring', or simply 'The Ring'.

Wagner wrote the libretto and music over the course of about twenty-six years, from 1848 to 1874. The four parts that constitute the 'Ring cycle' are, in sequence:

'Das Rheingold' (The Rhinegold)

'Die Walküre' (The Valkyrie)

'Siegfried'

'Götterdämmerung' (Twilight of the Gods)

Individual works of the sequence are often performed separately, and indeed the operas contain dialogues that mention events in the previous operas, so that a viewer could watch any of them without having watched the previous parts and still understand the plot. However, Wagner intended them to be performed in series. The first performance as a cycle opened the first Bayreuth Festival in 1876, beginning with 'Das Rheingold' on 13 August and ending with 'Götterdämmerung' on 17 August.