Willem Piso was a Dutch physician and naturalist who participated as an expedition doctor in Dutch Brazil from 1637 – 1644, sponsored by count Johan Maurits van Nassau-Siegen and the Dutch West India Company. Piso became one of the founders of tropical medicine.

Dutch Brazil, also known as New Holland, was a colony of the Dutch Republic in the northeastern portion of modern-day Brazil, controlled from 1630 to 1654 during Dutch colonization of the Americas. The main cities of the colony were the capital Mauritsstad, Frederikstadt, Nieuw Amsterdam (Natal), Saint Louis, São Cristóvão, Fort Schoonenborch (Fortaleza), Sirinhaém, and Olinda.