Art fakes revealed in National Gallery exhibition

An Allegory Bought by the National Gallery in 1874, this painting was believed to be by Italian artist Sandro Botticelli. It has since been revealed as a fake Photograph: Ben Stansall/AFP/Getty Images Photograph: Ben Stansall/guardian.co.uk Venus and Mars by Sandro Botticelli (c1485) The is the real Botticelli bought along with the fake in 1874 Photograph: National Gallery, London Photograph: guardian.co.uk Portrait of Alexander Mornauer (c1464-88) This painting was altered to resemble a Holbein, and a bright blue background added using a pigment not available until the 18th century Photograph: National Gallery, London Photograph: guardian.co.uk The same portrait, returned to its original state Photograph: National Gallery, London Photograph: guardian.co.uk The Virgin and Child With an Angel Bought by the National Gallery in 1893. After another version of the painting appeared on the market in 1954, technical examinations confirmed that the newly discovered painting was actually the original Photograph: Ben Stansall/AFP/Getty Images Photograph: Ben Stansall/guardian.co.uk An Old Man in an Armchair This 17th-century image was created by an unknown student, emulating Rembrandt Photograph: National Gallery, London Photograph: guardian.co.uk The Madonna with the Iris This painting, originally attributed to Albrecht Dürer, is now believed to have been painted by other artists at his workshop Photograph: Dominic Lipinski/PA Photograph: Dominic Lipinski/guardian.co.uk Woman at a Window (1510-30) This painting by an unknown Italian artist was acquired by the National Gallery in the mid-19th century as a portrait of a brunette woman. Following an investigation, it was revealed the painting had been altered with a heavily discoloured varnish to satisfy more restrained Victorian tastes Photograph: Ben Stansall/AFP/Getty Images Photograph: Ben Stansall/guardian.co.uk Italian Portrait Group This ancient-looking painting dates back no further than the early 20th century Photograph: Dominic Lipinski/PA Photograph: Dominic Lipinski/guardian.co.uk