During the Renaissance, medical research progressed as physicians studied anatomy and experimented with new treatments, building on knowledge from Arabic writings. The Black Death spurred experimentation to find treatments for the plague. Anatomical drawings by Leonardo da Vinci and dissections by Vesalius advanced knowledge of the human body. Surgery was still risky and performed without strong pain relief. Herbal medicines were developed to treat various diseases. Hospitals began to be established centers of medical care.