You have block printing emerge during the Tang Dynasty, but during the Song Dynasty, it gets perfected and it becomes more efficient with movable block print. You have the compass being perfected, especially for naval use, the boats being perfected. You see this reinvigoration, and really the high point of the Chinese civil service. You see the emergence of Neo-Confucianism. But one question is, well, what allowed all of this innovation to take place? And also what allowed for the stability of the Song Dynasty? When you look at it on the timeline like this that's covering over 2,000 years, it might not look that long, but when you actually think about it, this is over 300 years of dynastic rule by one dynasty.