Innovations are the lifeblood of progress in Crusader Kings III, representing the technological, cultural, and societal advancements that shape your dynasty's destiny. They are divided into three main categories: Military, Intrigue, and Stewardship, with further subdivisions based on culture and religion. The spread of Innovations is a complex but vital mechanic that allows your realm to benefit from the discoveries of others, and for your own discoveries to ripple outwards.
How Innovations Spread
Innovations primarily spread through cultural proximity and the actions of your characters. If a neighboring culture has an Innovation that you do not, there's a chance it will begin to spread into your realm over time. This spread is influenced by factors such as the diplomatic relationship between your ruler and the ruler of the innovating culture, the number of shared borders, and the presence of characters with high Learning or Stewardship skills in your court who are exposed to these new ideas. Furthermore, characters who travel, participate in events, or engage in diplomacy with fore courts can act as conduits for Innovation, bringing new knowledge back to their homeland.
Accelerating Innovation Spread
To speed up the adoption of Innovations, consider actively pursuing diplomatic relations with cultures that possess the technologies you desire. Arranging marriages with members of those cultures or sending your courtiers to learn from them can significantly boost the spread rate. Investing in your own realm's research by appointing educated advisors and constructing relevant buildings, such as universities or libraries, will also accelerate your own Innovation development and make your Innovations more likely to spread outwards. Pay close attention to the "Innovations" tab in your realm's menu to track the progress of new ideas and identify which ones are closest to being adopted.