The first modern military scuba divers were the World War II Italian commando frogmen, of Decima Flottiglia MAS (now "ComSubIn": Comando Raggruppamento Subacquei e Incursori Teseo Tesei) which formed in 1938 and was first in action in 1940. Originally these divers were called "Uomini Gamma" because they were members of the top secret special unit called "Gruppo Gamma", which originated from the kind of Pirelli rubber skin-suit nicknamed muta gamma used by these divers. Later they were nicknamed "Uomini Rana", Italian for "frog men" This special corps used an early oxygen rebreather scuba set, the Auto Respiratore ad Ossigeno (A.R.O), a development of the Dräger oxygen self-contained breathing apparatus designed for the mining industry and of the Davis Submerged Escape Apparatus made by Siebe, Gorman & Co and by Bergomi, designed for escaping from sunken submarines. The Italian frogmen trained in La Spezia, Liguria, using swimfins, rubber dry suit, and the new A.R.O. scuba unit. After Italy declared war, the Decima Flottiglia MAS (Xª MAS) attempted several attacks on British naval bases in the Mediterranean between June 1940 and July 1941, but none was successful, because of equipment failure or early detection by British forces. On September 10, 1941, eight Xª MAS frogmen were inserted by submarine close to the British harbour at Gibraltar, where using human torpedoes to penetrate the defences, sank three merchant ships with limpet mines before escaping through neutral Spain. An even more successful attack, the Raid on Alexandria, was mounted on 19 December on the harbour at Alexandria, again using human torpedoes. The raid resulted in disabling the battleships and together with a destroyer and an oil tanker, but all six frogmen were captured.
