The Marcos League was the instigator of the succession wars. A loose federation of trade and mercantile guilds the league formed to throw off the oppressive yoke of the USF. In the wars that followed the League got very good at enhancing diplomatic relations with other planets for their own gain. In the end they forced the USF into a stale mate and sued for peace, creating the Human Interstellar Empire. They have since moved into the realm of intergalactic trade.