The first New York Fashion Week was created in 1943 by Eleanor Lambert.
New York Fashion Week,held in February and September of each year, is a semi-annual series of events (generally lasting 7–9 days) when international fashion collections are shown to buyers, the press and the general public. It is one of four major fashion weeks in the world, collectively along with those in Paris, London and Milan.
(https://en.wikipedia.org/wiki/New_York_Fashion_Week)
The Fashion Week is a week dedicated to fashion, in which the stylists and fashion houses present their new collections and fashion designs on the catwalk.
The Fashion Week takes place twice a year : the winter collections are present in February-March, those of summer in September-October.
Four cities host the Fashion Week during 4 weeks, always in the same order : New York, where the expected parades are Lacoste and Ralph Lauren, at the Fashion Week of London, the expected parades are Burberry, Topshop and Paul Smith, that of Milan, Gucci, Fendi, Georgio Aramani and Valentino, comes then and finally, the Fashion Week of Paris where the expected parades are Saint Lauren, Chanel, Christian Dior, Louis Vuitton and Givenchy.
Paris is the only city which presents « high fashion » shows. The ready-to-wear is immediately marketable, we find a major part of the clothes of the Fashion Week 6 months after in shops.
The high fashion is not always marketed, it is for more well-off clientele.