The Crossing is an important event in the history of Enroth, and is mentioned in Might and Magic VI: The Mandate of Heaven. According to the legends, the races inhabiting Enroth traveled to the planet in a great ship, and the journey took so long that three generations of travelers were born, lived, and died before they reached their destination.
All of the greatest artifacts from before the Silence came from the ship. The ship itself was buried in the sand, becoming the Tomb of VARN.
The rumors also state that the reason why dwarves are so short is that before the Crossing, they lived in a place with higher gravity, with caused them to be short and strong.