Cardano's first main net launches. The main net is simplistic - it's centralized and there isn't staking and smart contract functionality. Only Cardano's centrally managed nodes can publish transactions and users are able to connect to these nodes to create wallets and transact ADA. This marks the start of Cardano's Byron development era.
Cardano's development team describes Cardano's two different development phases with this passage in their roadmap: "We are currently in Byron, the bootstrap phase, where we are making improvements. These include to the code, for example in the wallet backend, and debugging. We will improve the design of Daedalus and make integration through APIs to third parties simpler. We will then move from Byron to Shelley, where the network becomes decentralised. Over the next 18 months work will be done that contributes to stability, interoperability and governance. Throughout the arc of development, Cardano’s protocols will increase in complexity, interdependence and use more exotic cryptographic primitives."