Wagner revolutionised opera.
In a series of "music dramas" such as Tristan und Isolde, Parsifal, Tannhauser, The Flying Dutchman, and most of all, his epic tetrology Der Ring des Nibelungen, Wagner abolished the traditional distinction between recitative and aria and pioneered a new through-composed style of opera that avoids traditional cadences.
Penning his own librettos (libretti) based on Nordic tales and famous for their gigantic scale, Wagner's works also initiated a move away from traditional tonality.
His own opera house at Bayreuth built specially to house presentations of his works continues to thrive today, run by a succession of his descendants - Weiland and Wolfgang Wagner (grandsons) in their time they were both directors.
Wagner's lasting effect and legacy on the opera world has been immense with the iconic large soprano in winged helmut frequently being seen as a representation of all things opera.
Wagners genius is unquestionable- and despite his daughter in law's close friendship with Adolf Hitler and Hitler's championing of Wagners work that brought smear and disrepute on the Wagner name for many years, his work today retains its own special place in the world of opera.