This translates to "Lord have mercy, Christ have mercy, Lord have mercy." This movement is written in a double fugue. The fugue is a contrapuntal technique for two or more voices built on a theme, which is introduced at the beginning and recurs frequently in the composition and within the other voices. A fugue has three sections, which are exposition, development and return of the subject to the tonic. In Renaissance music fugue was used for imitative works, moved on to the 17th century and became elaborate, but in the classical era it was no longer seen as the center of compositions. A double fugue has two subjects occurring at the same time. A common double fugue would be seen in Bach's Mass in B minor. Below is an example of the double fugue seen in