Ethereum was officially launched on July 30, 2015. This marked the release of the first version of the Ethereum blockchain, known as Frontier. The launch was a significant milestone in the world of blockchain technology, enabling developers to create and deploy decentralized applications (dApps) and smart contracts on the Ethereum network.

1. **Development Timeline**

The journey to Ethereum's launch began with the publication of the Ethereum whitepaper by Vitalik Buterin in late 2013. This document outlined the vision for a decentralized platform that could support a wide range of applications through smart contracts.

• 2013: Vitalik Buterin publishes the Ethereum whitepaper.
• 2014: Ethereum conducts its Initial Coin Offering (ICO), raising over $18 million in Bitcoin to fund development.
• July 30, 2015: Ethereum's Frontier version is launched, allowing developers to start building on the platform.

2. **The Frontier Release**

The Frontier release was aimed at developers and provided the first opportunity to interact with the Ethereum blockchain. It allowed users to mine Ether (ETH), the native cryptocurrency of Ethereum, and to deploy smart contracts. The release was considered a "beta" version, as the Ethereum team expected to iterate and improve the platform based on user feedback.

3. **Key Features of the Frontier Release**

The Frontier version introduced several important features:

• Mining: Users could mine Ether using their computational power, contributing to network security and transaction validation.
• Smart Contracts: Developers could write and deploy smart contracts using the Solidity programming language, enabling automated agreements without intermediaries.
• Ethereum Virtual Machine (EVM): The EVM allowed for the execution of smart contracts in a decentralized manner, ensuring that all nodes in the network could agree on the state of the blockchain.

4. **Sample Code: Creating a Simple Smart Contract**

Here’s a simple example of a smart contract written in Solidity, which was introduced during the Frontier release:

solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract SimpleStorage {
    uint256 private storedData;

    function set(uint256 x) public {
        storedData = x;
    }

    function get() public view returns (uint256) {
        return storedData;
    }
}

This smart contract allows users to store a number and retrieve it later. The set function updates the stored number, while the get function retrieves it.

5. **Post-Launch Developments**

After the Frontier launch, Ethereum underwent several upgrades and improvements, leading to subsequent versions such as Homestead in March 2016 and Metropolis, which was split into two phases: Byzantium and Constantinople. Each upgrade introduced new features, improvements, and optimizations to the Ethereum network.

6. **Conclusion**

The launch of Ethereum on July 30, 2015, was a pivotal moment in the blockchain space. It opened up new possibilities for decentralized applications and smart contracts, laying the groundwork for a vibrant ecosystem that continues to grow and innovate. Today, Ethereum remains one of the leading blockchain platforms, with a wide range of applications across various industries.