Mathematica (with apologies to Stephen Worlfram)
"Give me but one firm spot on which to stand, and I will move the earth."
In rennaisance Florence, a seemingly random meeting between Machiavelli, Michelangelo and a mysterious stranger from Athens sparks a conspiracy that will change the world. Armed with the secret lost writings of Archimedes, the three hatch a plan to unite the warring states of Italy and rule the world in a new golden age of enlightenment and knowledge. It doesn't work.
At first, armed with their newfound method of manipulating the world through the knowledge of Plato's pure mathematical objects according to the priciples of Archimedes and the laws of Euclid, the cabal makes great strides towards a better world. But the Papcy is not amused. Under the guidance of the newly named Cardinal DaVinci, the armies of rome march armed with engines of war such as the earth has never seen. The engineering geinus of DaVinci forms an equal foe to the mysticism and machinations of the Cabal. Italy seems destined for a long bloody war.
But what of these stirrings in Germany, where un unheralded genius dares to speak that Euclid is wrong, that light has a definite speed, and the parallel lines may indeed meet.
In a universe where fetishized mathematical principles yeild awesome powers and improbable feats of engineering are possible, anything is possible. All your rennaisance favorites are back, with new, amazing abilities fighting the intellectual and even the material battle for mastery of the human soul.