The conspiracy traces to Nuremberg the 14th and 15th centuries and the ascendency of the BGMG under the House of Guelph. In the 15th century cartography was entering an exciting new time. New lands were being found. Previously uncharted islands, indeed even continents, were being added to world maps. The BGMG found a splendid way to find massive amounts of Royal funding (commissions). If you convince burgeoning world powers that their maps are completely inadequate and only a globe can accurately depict the earth, one is in for a lot of commissioned work. Add to that the fact globes became a status symbol in vogue among the wealthy of the period and you have an enormous cash cow.
But this ignores (or only scrapes) the actual depth of the plan. The goal of the BGMG was not map-making or wealth from it. The simple goal was power. To gain influence at court led to all sorts of potential for abuse of such power. This was an age where the court was the center of power; "scientists" vied to have their ideas heard. The difference between living in obscurity and becoming a household name was a "discovery" away.
Further, it was the Age of Discovery, where untold wealth might be a ship's journey away for a kingdom -- indeed this was the genesis of European imperialism. Map makers
invented islands and continents to attain funding for expeditions. The closer you find yourselves to the strings of power, the more opportunity for corruption.