On the latest episode of Block Stars, David Schwartz—the creator of the XRP Ledger and current CTO of Ripple, sat down with Stefan Thomas, former CTO of Ripple and current CEO of Coil, to discuss the early days of blockchain, and their time working together on the XRP Ledger, Codius and Interledger Protocol (ILP).

Most people don’t realize that prior to Ripple, David and Stefan both used to work on Bitcoin. Stefan helped create BitcoinJS, which is a JavaScript implementation of the Bitcoin blockchain. David tinkered around with Bitcoin Core, as a C++ developer with a lot of experience using applied cryptography to build distributed systems, and helped the early core contributors solve some problems via the Bitcoin forum.

Both were inspired by the decentralized nature of the technology, but also recognized some issues early on.