The Oresteia is the only surviving trilogy of these ancient Greek plays, originally performed at the festival in Athens in 458 BC.
The increase in sequels in recent years means there are a number of franchises that have produced three films, often with II and III appended to their title as an indication.
Another example can be found in the Guns N' Roses songs "November Rain", "Don't Cry" and "Estranged", whose videos are considered a trilogy.
The Weeknd's 2012 compilation album Trilogy is a remastered and remixed collection of his 2011 mixtapes House of Balloons, Thursday, and Echoes of Silence.
Taylor Swift's eighth studio album, Folklore, contains the songs "Cardigan", "August" and "Betty", a trilogy that tells a story of a love triangle.