The first known use of the method comes from 1446, when Leon Battista Alberti explored and attempted to lift the ships of Emperor Caligula in Lake Nemi, Italy.
In the 19th century, the standard copper helmet diving gear was developed, allowing divers to stay underwater for extended periods through a constant air supply pumped down from the surface through a hose.
Nevertheless, the widespread utilisation of diving gear for archaeological purposes had to wait until the 20th century, when archaeologists began to appreciate the wealth of material that could be found under the water.
This can simply mean the diver swimming around and noting objects of interest of the seafloor, but it is usually supplemented through the use of a wide array of tools, such as hand-held metal detectors, lines to guide the search and make it more systematic.
At this stage, diving is necessary to take the most basic of measurements and apply methods of surveying similar to those used on land, including trilateration, grid division and photography.
For example, trowels, brushes and other tools are used to move the soil, but the diver's movements might also disturb the sediment, which can lead to inadvertent damage of the site, but which can also be utilised to delicately expose artifacts.
Perhaps the greatest risk is posed by decompression sickness (DCS), caused by excessive concentrations of nitrogen from the breathing air dissolved in the diver's tissues, and which can be painful, debilitating and in some cases, fatal.
[2] In 1900, Greek sponge divers discovered numerous statues under the water near the island of Antikythera, deposited as a result of the sinking of a ship from the first century BCE.
It has been dated to the late 14th century BCE, and the material retrieved, including large amounts of copper and tin, ceramics, precious metals, tools, weapons and other objects, reveal much about the long-distance trade and manufacturing practices of the time.
Early investigations of the site were conducted by the amateur underwater archaeologist Kamel Abul-Saadat in 1961 and then by a UNESCO mission led by Honor Frost.
Following damage to the remains of the lighthouse by the construction of a concrete wall to defend a nearby medieval fortress, a Franco-Egyptian team under the leadership of Jean-Yves Empereur conducted salvage inspection and excavation of the site from 1994 to 1998.