Constantinople managed to keep the secret of Greek Fire.
Roman emperor Constantine the Great picked Constantinople as his new capital because it could be easily defended against barbarians. He did this although (I think) he faced no barbarian threat. This worked out very well.
Although Japan had been a very closed society, when the Japanese saw in 1853 how much more advanced the American navy was from its own the Japanese quickly modernized and became one of the few Asian countries to escape western colonization (until after WWII at least).
Constantinople managed to keep the secret of Greek Fire.
Silk was kept secret for centuries, although not forever.
I'm currently working on a research project for MIRI, and I would welcome feedback on my research as I proceed. In this post, I describe the project.
As a part of an effort to steel-man objections to MIRI's mission, MIRI Executive Director Luke Muehlhauser has asked me to develop the following objection:
In Luke's initial email to me, he wrote:
Luke and I brainstormed a list of potential historical examples of people predicting the future 10+ years out, and using the predictions to inform their actions. We came up with the following potential examples, which I've listed in chronological order by approximate year: