The first cryptocurrency coin, Bitcoin, was launched on January 3, 2009.
It was created by a pseudonymous person or group known as Satoshi Nakamoto. On that date, the Genesis Block (Block 0) of the Bitcoin blockchain was mined, officially starting the Bitcoin network.
Key milestones:
Whitepaper published: October 31, 2008
Title: Bitcoin: A Peer-to-Peer Electronic Cash System
Genesis block mined: January 3, 2009
Bitcoin version 0.1 released: January 9, 2009
Bitcoin laid the foundation for all other cryptocurrencies that followed.