In 1968 the Rembrandt Research Project began under the sponsorship of the Netherlands Organization for the Advancement of Scientific Research; it was initially expected to last a highly optimistic ten years. Art historians teamed up with experts from other fields to reassess the authenticity of works attributed to Rembrandt, using all methods available, including state-of-the-art technical diagnostics, and to compile a complete new catalogue raisonné of his paintings. As a result of their findings, many paintings that were previously attributed to Rembrandt have been removed from their list, although others have been added back. Many of those removed are now thought to be the work of his students.