The Great Kingdom exist many years ago after Jesus' death. It was a hard-partying kingdom that has the whole world dancing, gave freedom, have giant monument built. All was good until it started a weed monopoly and got the whole world smoking. One day, twenty kings of 20 different kingdoms were so high that they wanted more but the Great Kingdom told them to shut up. Angered by this; they decided to form an alliance to kick it's ass.
Despite being high and the Great Kingdom being super-powered and super-advanced, the twenty kingdoms manage to deliver a wedgie. Knowing it's going to lose the war, the Great Kingdom manage to hide weed carefully and wrote on a indestructible block of stone with some Lost Technology "tm" and had it smell of weed as pointed out by Robin who smelled the stone and become high. It later became known as the poneglyph.
After the war, bomb dropped and the twenty kings bend togather a band called "World Government", went on a worldwide tour and got the world togather. They viewed Great Kingdom's ideals an dangerous one, banned researching poneglyph and created a hundred years void. The Great Kingdom's name was Achoo!