Researchers have concluded after two years of study that a disputed oil sketch was in fact painted by Dutch master Rembrandt.

Museum Bredius, which is in possession of the sketch, said on Thursday that the discovery was first made by Dutch art historian Jeroen Giltaij when he was conducting research for his soon-to-be-published book on Rembrandt paintings.

"The discovery was a pleasant surprise," Boris de Munnick from Museum Bredius said. "We already had one artwork of Rembrandt, and now we suddenly have two."

"From the start, I was certain that this sketch must be a Rembrandt," Giltaij told Reuters. He said it is hard to distinguish between works created by the famous painter and ones made by his followers. "But this sketch is so splendidly painted, it just had to be made by Rembrandt."

He added, however, that some might contest this claim. "That's how it goes in the Rembrandt art world."

After performing a restoration on the sketch, Museum Bredius agreed with Giltaij and contacted Amsterdam's Rijksmuseum, home to Rembrandt's masterpiece "Nightwatch." Its researchers performed a technical analysis on the small oil sketch. They concluded the same: it was painted by Rembrandt.

Though the sketch resembles Rembrandt's 1633 painting "The Raising of the Cross," dendrochronological research conducted on its panel found that the plank dates from 1634 and that it could have been used between 1642 and 1645, meaning that the artwork could not have been a preliminary sketch of the bigger painting.

"More research will be done to find out what the sketch's purpose was," said Giltaij. "But that investigation will start with the notion that the sketch is a Rembrandt."

Rembrandt Harmenszoon van Rijn is a Dutch painter and printmaker. He is one of the most important painters in European and Dutch art history. He lived in the Dutch Golden Age, when the Netherlands made a breakthrough in trade, science and art. He is also known as the "painter of light and shadows."