Johannes Vermeer of Delft left behind fewer than 50 paintings when he died aged 43 in 1675. Those that survived have beguiled art lovers for more than a century: intimate domestic scenes, such as a girl reading a letter at an open window, or a maidservant absorbed in pouring milk, bathed in soft, gentle light. As Vermeer’s output was so small, it is an event when a painting is declared to be by his hand. But there are few precedents for a recent tussle over the artist. One painting has been declared definitively “a Vermeer” by one museum, while another has downgraded it.

In October, the National Gallery of Art in Washington DC announced the results of painstaking research into a work in its collection, long credited to Vermeer. Girl with a Flute was not by Vermeer, but an associate, it said. Less than a month later the Rijksmuseum in Amsterdam, which is borrowing that painting for a major new Vermeer exhibition in 2023, reached the opposite conclusion about the same work. It was “crystal clear”, the Rijksmuseum said, Girl with a Flute was a Vermeer.