Messerschmidt was German-Austrian, and sculpted the heads in 1770-72. At this time he suffered from delusions and hallucinations, or a “confusion in the head” as his employer, the Viennese Academy of Fine Arts, described it. In 1774, Messerschmidt was expelled from the academy.
In 1781, Messerschmidt stated that the heads had been created as a record of his facial expressions on pinching himself to alleviate the pain of an illness he suffered, known now to be Crohn’s Disease. He intended to sculpt the 64 “canonical grimaces” of the human face using his own as a template.
Messerschmidt also claimed that he was physically tortured by “the Spirit of Proportion”, an ancient being who guarded the knowledge of harmony and who was angered by Messerschmidt’s disharmonius work. Personally, I think they're tremendous works, and wouldn't look at all out of place in an exhibition of contemporary work today.