A camera born in France
It is a well known fact that a full-scale all-weather camera NIKONOS (see photo) launched in 1963 was not originally designed by Nippon Kogaku K.K. (present Nikon Corporation).
The original was Calypso (1961), a camera which is resistant to water pressure at the depth of 50 meters, designed and made by LA SPIROTECHNIQUE well known for its diving apparatus including aqua lung.
Its name Calypso is, directly, associated with the name of a marine research ship of Jaques-Yves COUSTEAU, ex-captain of French Navy who is the inventor of aqua lung and famous for his science film "Le Monde du Silence" which was much talked about underwater shooting scenes (originally it is the name of an island nymph of Greek myths).
The product name of this camera for a certain area of Europe succeeded this name in the form of "Calypso/Nikkor" even at later days.
It is not clearly known why this "Calypso" was to be made by Nippon Kogaku as 'NIKONOS', but it can easily be guessed that LA SPIROTECHNIQUE may have judged that, "it might be better to have some experienced camera manufacturer make than to make it by oneself", since they are originally not an optical apparatus maker (= an affiliated company of a French gas maker, L'Air Liquide S.A.).
In fact, this offer of technology transfer and the right of world-wide (except EEC countries at that time) distribution was brought to Nippon Kogaku by LA SPIROTECHNIQUE. It is interesting that 'T' company, a Japanese industrial gas manufacturer mediated between two parties.
Nippon Kogaku had once sold a housing for underwater photography which houses a range-finder type Nikon (Nikon S2, SP, S3 etc.) under the product name of "Nikon Marine."
It was supposed to be the reason because that kind of experience was appreciated that Nippon Kogaku was selected among many optical instrument manufacturers.