The earliest known writings on the circulatory system are found in the Ebers Papyrus (16th century BCE), an ancient Egyptian medical papyrus containing over 700 prescriptions and remedies, both physical and spiritual.
An English translation of the papyrus was published by Paul Ghalioungui.
papyrus | Papyrus 75 | Papyrus Design Group | Papyrus 45 | Papyrus 66 | Papyrus | John Ebers | Ebers Papyrus | Cyperus papyrus | Reisner Papyrus | Papyrus's | Papyrus Harris 500 | Papyrus 93 | Papyrus 88 | Papyrus 37 | Magdalen papyrus | Judicial Papyrus of Turin | Ipuwer Papyrus | Charioteer Papyrus | Berlin Papyrus |
The antiquity of these tools is well documented in early writing, such as the Egyptian Ebers Papyrus of ~1550 BCE (the oldest preserved piece of medical literature) and the Old Testament (Numbers 11:8 and Proverbs 27:22).