Apr 2014: The Yellow Paper of Ethereum was written by Dr.Gavin Wood, a blockchain expert who started working with Buterin. The Yellow paper is the technical specification of how Ethereum works. Developing software for Ethereum and launching it required huge effort and financial resources. To fund the project Ethereum announced presale for ether coins. Ether is the currency of ethereum blockchain.
June 2014: Ethereum Foundation was created as a result of legal and financial complexities of fundraising. It is a non profit organization which has the purpose to manage the funds that were raised from ether sale.
July 2014: Ethereum launched 42 day presale and received 30 000 bitcoin worth $18 million at that time by selling 60 million ether. Throughout 2014 frequent blog posts from the developer team on Ethereum’s blog helped keep the enthusiasm, constantly attracting developers and enthusiasts.
2015: The initial version of Ethereum is launched and developers began writing smart contracts and decentralized applications.