Just found this photo of these events which lead to the foundation of bitcoin and can be counted as a milestone to it's development. So it all started in 1976 when cryptography's concept was introduced which gave an idea of PGP key and signatures and secure distribution channels for transfer of information. Then the best minds worked together in the direction of cryptography. Looks like 2001-2008 was the time when Satoshi took charge of the development of bitcoin and by the end of 2008 launched it.