Slate has run an interesting slide show presenting virtual history of credit cards. The merchant specific cards came in use as early as 1930s, when companies started offering, what they used to call “charge-plates” to their customers. However, the individual who is credited with introduction of the current credit card system is Frank McNamara. Frank McNamara was one of the founders of Diners’ Club.

source - www.slate.com

However he got the idea of a Credit card system from an embarassing situation. He was having dinner at a restaurant and when the cheque arrived he realised that he had forgotten the wallet. That’s where he got the idea of having a system where one can “buy now and pay later, any time, anywhere”. The first card which was essentially for eating out at restaurants was a simple wallet-sized card made of paper. However, the concept behind it was revolutionary and within 60 years it has revolutionized shopping habits of people world over.