Let’s begin by understanding what being Byzantine fault tolerant actually means. The term Byzantine fault tolerance is derived from a hypothetical scenario called the “Byzantine General’s Problem”. This hypothetical scenario was developed to describe a situation in which, in order to avoid failure of a distributed system, the system's actors must agree on a concerted strategy, but some of these actors are unreliable. It uses a planned attack on an enemy city by four Byzantine generals. These generals and their armies are each occupying a different side of the city and so are totally separated from each other, making direct, coordinated communication impossible. In order to plan their attack – or retreat – they must use their own messengers to handle communication and so they each send their messengers to share their plan with each other. All decentralized networks (distributed ledger, such as a blockchain) have independent nodes that act like the byzantine generals in the hypothetical situation above. These nodes must come to an agreement, or consensus, on things like: transactions submitted to the network, the ordering of those transactions, and the state of the network itself. These network nodes are likely separated from each other geographically, virtually, architecturally, and sometimes even ethically.