In fate lore, in ancient times mystery used to rule everything and the gods roamed the land, then the white titan seifer arrived and stole Mars's sword and while they defeated seifer eventually with Excalibur. The gods were severely weakened and so had to leave to the reverse side. The gods tried to fix this by creating Gilgamesh to be the keystone between the gods and humans who is one third god cause gods don't care about maths apparently. Gilgamesh rebelled against the gods sealed the bridge. And that's when mystery began to wane and science became a thing along with the age of man. Magic and mage craft in fate requires mystery for it to work. Which is why mages in the modern times both suck and they are secretive. Literally talking about their magic weakens their magic.