The Merge was executed on September 15, 2022. This completed Ethereum's transition to proof-of-stake consensus, officially deprecating proof-of-work and reducing energy consumption by ~99.95%
The Merge was the joining of the original execution layer of Ethereum (the Mainnet that has existed since genesis) with its new proof-of-stake consensus layer, the Beacon Chain. It eliminated the need for energy-intensive mining and instead enabled the network to be secured using staked ETH. It was a truly exciting step in realizing the Ethereum vision—more scalability, security, and sustainability.
With the EthereumPoW Hard Fork, any wallet address that had ETH tokens on the ERC20 mainnet before the snapshot will have the equivalent number of ETHW tokens on the EthereumPoW mainnet.