I found this fabulous article about Paul Delaroche and The Execution of Jane Grey at the Times online.

An excerpt:

Lady Jane Grey passed from a private collection into British hands and was left to the nation at the turn of the 20th century. Its fame, however, had evaporated, and by 1928 it was kept in the basement of what is now Tate Britain. When the building was flooded in that year, Delaroche’s canvas was removed from its frame, rolled up and put away. Thirty years later it was apparently forgotten. In 1959 the painting was listed as “destroyed”. It was rediscovered only by accident, when in 1973 a young researcher looking for another large-scale painting asked conservators at the Tate to unroll a collection of long-ignored canvases. Lady Jane was one of them, and turned out to be almost perfectly preserved. Transferred to the National Gallery, it was put back on display, and swiftly became one of the most popular works on show.

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