Explore the evolution of multi-threading models in Paradox grand strategy games through this comprehensive conference talk. Delve into the challenges of simulating complex historical scenarios in real-time, focusing on politics, economy, warfare, diplomacy, and demographics. Examine three distinct threading models: the "old" model used in long-running titles like Europa Universalis IV, Hearts of Iron IV, and Stellaris; the "current" model introduced with Crusader Kings 3; and potential future approaches for upcoming games. Gain insights from French C++ expert Mathieu Ropert as he discusses how Paradox has adapted its threading strategies over 20 years to meet increasing computational demands and maintain fluid gameplay experiences.