2019 is the year of Rembrandt van Rijn (Leiden 1606-1669 Amsterdam): it has been exactly 350 years since this world-famous Dutch painter passed away. Over the course of his life he created an estimated 350 paintings, 374 etchings and 1500 - 2000 drawings. The authenticity of Rembrandt's work is still a common discussion point within the art world. Nowadays, only 78 drawings can be attributed to Rembrandt with high certainty, thanks to their signature or contemporary sources. This core group now functions as a key in indentifying his other drawings.
If you wanted to be an artist back in the Golden Age, you would have to study under a professional artist. Rembrandt accepted pupils quite early on. He taught them to work in his own style. As their first lesson, his students would have to copy etchings, drawings and paintings by his hand. Drawings were mainly used as studies in his studio, which is why they are rarely signed. That makes it hard to distinguish Rembrandt's drawings from those of his students.