Michelangelo only sign one piece of artwork.

When it was unveiled a proud Michelangelo stood by and watched as people admired the beautiful Pieta. However, what was pride quickly turned into anger as he overheard a group of people attributing the work to other artists of his time. That anger caused Michelangelo to add one last thing to his sculpture. Going down the sash on the Virgin Mary, Michelangelo carved his name. He later regretted that his emotions got the best of him and vowed to never sign another one of his works again.