THE HAGUE — The painting was sliced down the middle and straight through its center in the 19th century, probably to be sold as two Rembrandt portraits. At some point in the next 40 years, it was sutured back together with pieces of an entirely different canvas, and layered with paint to cover up its scars.

In 1898, the director of the Mauritshuis Royal Picture Gallery here proudly displayed it in the museum as “Saul and David,” one of Rembrandt’s most important biblical works. Then in 1969, a top Rembrandt authority discredited the painting, and for years it hung next to a label that read, “Rembrandt and/or Studio,” a serious demotion.

Now, after eight years of examination and restoration by the museum’s own conservators — with support from researchers from various outside institutions, like the Delft University of Technology, the National Gallery of Art in Washington, the Netherlands Institute for Art History and Cornell University — the Mauritshuis has reclaimed the painting as an authentic Rembrandt, saying it was painted in two stages by the master’s own hand, one of hundreds of surviving Rembrandt paintings.

The museum is to reveal its findings on Tuesday two days before it opens an exhibition, “Rembrandt? The Case of Saul and David.” The show is devoted entirely to this single work, which depicts the young hero David playing a harp for an elderly King Saul, who is moved by the music and uses a curtain to wipe away his tears.