Hippocrates, the Father of Medicine, proved the foundation for most of Galen's work, especially concerning humoral theory. He also studied the works of Herophilus and of Erasistratus whose works he went to a lot of trouble to refute in his book On Natural Faculties. He was well-known for criticizing other physicians of his time for publishing inaccurate information to the public. Though he himself performed on animals with some mistakes in his anatomical findings his work was far advanced for the time period.

Predecessors

Eventual Effects

The famed Persian philosopher and physician Avicenna is one of many that drew from Galen's theories. Galen discovered the medicine Theriac that was an effective antidote for most poisons, proved that the brain was the most important organ in the body, not the heart, and recognized that the kidneys produce urine. Galen's monotheistic faith, though not Christian, proved useful in acceptance of his writings by Muslim and Christian scholars.