The concept of non-fungible tokens (NFTs) was first proposed in a 2013 white paper by Dr. Greg McMullen, who is the founder of the blockchain platform AXEL. In the white paper, McMullen described how NFTs could be used to represent digital assets, such as digital art and collectibles, on a blockchain.
However, the first practical implementation of NFTs was made in the Ethereum blockchain, by a group of developers led by Matt Hall and John Watkinson who created CryptoPunks, a collection of 10,000 unique 8-bit characters, this happened in June 2017. They were one of the first non-fungible tokens created on the Ethereum blockchain and they were used as a proof of concept for the technology.
After that, the use of NFTs and their potential applications started to be explored by other developers and projects, and this led to the development of NFT marketplaces like OpenSea, Rarible, and SuperRare.
It’s worth noting that the NFT technology is still relatively new, and the field is still evolving, with new developments and use cases emerging all the time.