The document discusses the evolution of autonomous agents from early conceptions in artificial intelligence to modern implementations. It describes how agents were initially conceived as "thinking machines" that interacted with humans through symbolic manipulation and language. However, new approaches conceived of agents as operating in physical environments like animals, leading to a focus on embodiment, reactivity to the environment, and physical effects. This led to definitions of agenthood based on autonomy, reactivity, and potentially proactivity and sociality. Multi-agent systems then emerged as a way to simulate societies through the interaction of many autonomous agents without centralized control.