The circulation of blood within the body has been a subject of study for many thousands years. In ancient times, the Chinese recognized the fact that blood circulated through the blood vessels and developed theories on how such systems worked. Evidence also suggests that scholars in India had developed some knowledge of the circulatory system, with an emphasis on the pulse and its dynamic nature.
A broader understanding of circulation and the circulatory system was developed in the early 1600’s by a doctor named William Harvey.