Written by By Tiffany Ap, CNN

The Rembrandt van Rijn painting Thomas Tallis, 14th century, in question is a renowned example of the Dutch master's mastery.

The telling detail of the shoulder blade, which gives its all, was originally thought to be a Titian

Despite ample historical support for its authenticity, a workshop painting adrift in a local auction house has remained a mystery -- until now.

Image: PICENTHE AFP/Getty Images

"It is reasonable to assume that it is a Rembrandt, there's no question of that," Van Hoorn Museum Curator Tony Foos told Dutch news site De Telegraaf, which first broke the story.

"The window has four corners, while other paintings have five, but it still looks as if the window is made out of wood, which is very unlike Rembrandt's style."

The Thomas Tallis, as it was identified by De Telegraaf, is housed in the Tallis Institute in Amsterdam. The artist also painted the church and the adjacent portrait chapel for the wealthy congregation that regularly attended services there.

The painting's provenance rests with the Thomas Tallis Museum in the central Dutch city of Nijmegen, which was founded in 1976 as a repository for 14th-century artworks.

In 1993, before an American couple purchased the painting, it had been housed for more than a century in a municipal center in Tilburg.

Today, Thomas Tallis remains its central curatorial center. Visitors, visitors' board members and for a time, museum guests can gawk at the Portrait Chapel, where it's believed Rembrandt painted his own artworks in the 14th century.