Plutarch (De Primo Frigido, 950B), a Greek-turned-Roman philosopher of the 1st century CE, and Oppian (Halieutica, V.638, 646), a Roman poet of the 2nd century CE, both mention that divers would take a mouthful of oil before each dive. They claim that when the diver reached the bottom of their dive, they would spit out the oil so that he could see more clearly. They did not have helmets or protective lenses to aid in their sight in salt water, so they had to improvise. Some modern scholars, however, such as Dr. Frank J. Frost, have suggested that ancient Greek and Roman divers would take oil in their mouths for an entirely different reason. They argue that the divers would force the oil up through their eustachian tubes, the tubes that connect the nasopharynx to the middle ear, in order to protect their sensitive ear tissue from exposure to salt water. There does not seem to be any literary or archaeological evidence to prove this theory. However, if it does turn out to be true that the ancient Greek and Roman divers used oil this way, it could indicate that they had a more sophisticated understanding of human physiology than what many of the extant literary sources suggest.
Although there do not seem to be too many dangerous predators in the Mediterranean sea today, ancient historians claim that sharks were a definite problem for divers and even discuss ways in which divers tried to keep themselves safe from the carnivorous animal. For instance, the Roman historian Aelian, writing in the late 2nd/early 3rd century CE, states in his De Natura Animalium (On the Nature of Animals) that divers would blacken their hands and feet in order to try to avoid a loss of a limb from a shark attack (15.11). What makes this interesting is that to this day it is a widespread belief that sharks are discouraged by dark colors. Pliny the Elder, a Roman philosopher and author from the 1st century CE, figured out something that modern divers know – that swimming directly at sharks can scare them away (Natural History IX.152-3).
SO, HOW DEEP COULD THEY GO?
Another thing that modern scholars have been fascinated about regarding ancient Greek and Roman diving has been how deep the divers could have gone. Dives of 90 feet, according to the Rhodian Sea-Law (III.47), were well within ancient Greek and Roman divers’ ranges. Isidore of Charax (Athenaeus 3.93E) mentions pearl divers in the Persian Gulf who descended to 120 feet. While ancient literary sources must be taken with a grain of salt regarding the accuracy of the information given (ancient historians did like to exaggerate!), compared to modern ‘primitive’ divers, 90 feet for a dive does not seem that unreasonable.
DIVING AS A BUSINESS
Diving was a way of life for many poor men in Greece and Rome. The most common form of diving was for sponges, then the murex for ‘purple’ dye, and pearls, among other plants and animals common in the Mediterranean. According to the Rhodian Sea-Law (III.47-8), divers could keep part of their findings, depending on the depth at which they salvaged the objects. For instance, if gold, silver, or some other type of material was found at 8 fathoms (48 feet) down, the diver could keep 1/3 of what he found. If the objects were salvaged from 15 fathoms (90 feet) deep, then the diver could keep half, because of the danger to the diver that deep under water. However, if items were washed ashore or found 1 cubit (approximately 18 inches) below the surface of the water, then the diver could only keep 1/10 of what was found.
Diving in antiquity wasn’t just something that poor men did to earn a few drachmas, but was also a business. There were several corporations that were devoted to fishing and diving and were very competitive, especially in the Roman economy. Diving was also used for military operations. For instance, the earliest known documented organized military dive took place during the Peloponnesian War (431-404 BCE). The 5th century BCE Greek historian Thucydides writes that when the Spartans were being attacked on the island of Sphacteria, divers from the mainland were sent down to bypass the Athenian blockade and bring food and supplies to the besieged Spartan troops (History of the Peloponnesian War IV.26). Thucydides also describes an instance in which the military of Syracuse drove stakes into the bottom of the harbor around their anchorage to prevent Athenian triremes (a ship with three rows of oars) from getting through. The Athenians, however, sent divers to go down and cut through the stakes so that their ships could get through (HPW VII.25.6-8).