The Crossing

When the Hosts of Mankind fled The Old World to escape The Dimming, nine great armadas set out to cross The Plague Sea. This tumultuous time of great sacrifice and hardship is known as The Crossing. The Plague Sea sent forth monstrosities and calamities to drag humanity down into it's depths to be destroyed and forgotten. Humanity was nearly lost when a minor religious sect discovered ways to guard against the ravages of the Plague Sea. Sacrifices both personal and profound were made in attempts to appease the raging Sea. Sadly, the darker the blood sacrifices, the greater the abatement of the assault upon mankind's fragile fleets.  In the end, after seven months of madness, the remnants of humanity arrived on the shores of The Bright Lands.  Only five armadas survived to make landfall, and each of these mere fragments of the mighty fleets that left the Old World.  The leaders of these shattered armadas founded the five great cities that are the capitals of the Five Realms of Man.
There is a campfire tale, told by drunks and wastrels, of one ship from a sixth armada which crashed upon the shores of the Bright Lands, and the noble prince who's descendant will unite the Five Realms, but that is a flight of fancy that has not the first inkling of truth.