As found in the Scorn and the oldcity page
During that time, Brittany flourished, completely convinced that it was the last human kingdom in a world dominated by monsters of all sorts. Then, Mer'eric the Walker discovered by accident that a light could be seen, on clear days, from above the top of Nursen, the high mountain that dominates Brest, the Capital City of Brittany.
He spent ten years of his life to build the Great Heliograph, a device that could focus the sunlight into a wide beam, that could be used to send messages.
On the other side, the man now known as the “Mad Mage” was holding experiences about the properties of light. It was him that inadvertently attracted the attention of Mer'eric. And he quickly noticed the signs sent by the Great Heliograph, and built on his side a similar device.
But in Brest, things weren't as joyful as one could have thought.
People were thinking: “Those are dragons, trying to fool us ! Mer'eric as doomed us all !” And Mer'eric himself became afraid of the consequences of what he had done. So he hid his machine, and decided to cross the mountains to see by himself what had happened.