LONDON—A quintessentially British pre-Raphaelite masterpiece that has hung in a custom room in the Museo de Arte de Ponce in Puerto Rico since 1965 is making a rare appearance in Britain, reports the Guardian.

The Sleep of Arthur in Avalon, by Edward Burne-Jones, depicts the mortally wounded Arthur surrounded by queens, Amazons, and onlookers on the magical island of Avalon. The artist spent up to 18 years of his life working on the monumental painting, and is said to have still been working on it the day before his death in 1898.

Tate Britain director Stephen Deuchar calls the painting "the one that got away." When it was loaned to the museum in 1929 it was installed in a rear staircase, and when the Tate had an opportunity to buy it at a low price, it declined. Puerto Rico's governor bought the painting for a pittance in the early 1960s, when Victorian art was out of fashion. He created the museum to house the work and built up a substantial collection of British art around it.

Now the Puerto Rican museum has loaned the work to the Tate Britain, along with several other pre-Raphaelite pieces, while it completes a refurbishment of its galleries. The works will be on display in London until next February.