This work was called up by Napoleon

I never came across this term "call up" when it refers to work, any direction to understand this one is apperciated

At 7:46 video

That's the theory we have one main force and in other little tugs. How do you treat that mathematically? He pioneers that, solves it for the solar system, demonstrates that the solar system is stable far beyond anything Newton had imagined. This work was called up by Napoleon, Napoleon was not only everything we know him to be he was a great reader of mechanics and physics books.