The Revolutionaries were a group of humans who started worshipping The Ancient Ones long before Silvast was created. In return, they were granted a very powerful kind of magic. Thanks to this, they started thinking themselves above the law of the human world and were planning to take control of all humans. The Ancient Ones knew they couldn't let this happen and decided that they would take their magic away when they would try it. Therefore, the Revolutionaries decided that, if they couldn't rule this world, they would simply use their magic to create a new world, and they created The Twilight Realm and within it they started a settlement which grew out to a relatively large city, known as Silvast.
The inhabitants of Silvast, including Amnesty, are decendants of the Revolutionaries, though the Revolutionaries themselves are nowhere to be found.