Self-reinforcing

[Heretiv]

Right, Quebec City are my ally, and I have completed the Patronage tree.
Quebec seeks to be impressed by me producing a great engineer.
They gift me a great engineer.
Then relations with them improve due to all my hard work in making this engineer.

 

[Heerlo]

 

[Lites]

I love it when you have a large number of allied city states and this effect bounces around all of them as they each gift you a great person every dozen or so turns!