Diving has been taking place since primitive man was forced to forage for food in the sea. The first recorded divers though, are represented in Assyrian drawings in 900 B.C of armed divers using small breathing containers. Alexander the Great is known to of used military divers and a diving bell to assist in the removal of harbour obstacles in his Middle-East Campaigning. Over a thousand years later the Viking raiders are thought to of used divers for the same purpose. Back in those days divers had to be masters of breath-hold diving techniques to be successful. Some evidence does suggest though that methods of contained air supply were used even back then. This ranged from an inverted bucket to possible 'skins of air' as depicted on the Assyrian drawings. The history of diving for sport diving did not appear until much later...

By the 15th Century the recovery of valuables on board shipwrecks provided much of the impetus for salvage work underwater. The first was (arguably) the diving bell, the second was the diving helmet. Marvellous though both these inventions were they both required dedicated support from surface teams. A good many shipwrecks were salvaged using both of these most notably the Mary Rose (first salvage mission). Leonardo Da Vinci produced detailed drawings and plans of a scuba unit with self contained air and buoyancy, but these never made it off the drawing board as he instead concentrated on refining the diving bell.
The Industrial Revolution saw many inventions and leading the way in technological breakthroughs is Europe and America. In 1825 William James, an Englishman produced a workable design in which compressed air was carried in a circular iron reservoir around the waist. This device required no surface support and was totally independent. Unfortunately we have no record of James diving it so credit must go to Charles Condert who built a similar device and successfully used it many times in New York's East River before suffering a broken air tube and a quick death in 1832.
In 1865 Two Frenchmen, Rouqualyrol and Denayrouze made a sophisticated, lightweight diving set which was charged to 40 bar and then integrated into a full-face mask. Crucially the set contained a demand regulator which 'regulated' the air at the same pressure as the surrounding water. Another pioneer was Frenchman Louis Boutan who produced an air breathing set charged to nearly 200 bar. It was patented in Great Britain in 1918 by Japanese entrepreneurs as 'Ohgushi's Peerless Respirator'.

Commandant Yves le Prieur of the French Navy was the first to consider amateur sport diving in the sea. He produced a lightweight compressed-air apparatus with a regulator that was not quite fully automatic (air being supplied at a constant flow rather than on demand). He founded the first diving club in 1935 to train with his apparatus in Paris. The development of modern masks, fins and snorkel came from the breath-hold underwater fishermen who operated in the South of France in the 1920s and 1930s. The first of these was an American, Guy Gilpatric who used a pair of old flying goggles plugged with putty and painted over. His Russian friend created the first rubber mask with a single pane window. De Corlieu patented fins and Steve Butler, an Englishman used the first successful snorkel tube. The development of the first basic equipment was a joint effort from Americans, Russians, Frenchmen and Englishmen.

A young Frenchman Georges Commeinhes, developed the first fully automatic aqualung. It used twin cylinders with a full-face mask and air escaped from a special valve instead of from the edges of the mask. It had a pressure gauge and a demand valve mounted between the shoulder blades. The cylinder pressure was 150 bar and the French Navy were so impressed by it they approved it for use. Had it not been for the WW2 erupting two years later this may of developed into the divers choice of equipment but unfortunately he was killed in 1944. Jacques Cousteau, another French Navy Officer had also been working hard to produce an effective sports aqualung having been introduced into the sport by his Navy companions.

In 1942 he combined with Engineer Emile Gagnan to produce a new regulator with an inlet and exhaust tube that was fully automatic. With this development the modern aqualung was born.