Our ancestors came to this world more than a thousand years ago from a place called Earth. According to the scriptures, it was a world full of miracles and inventions we can't even comprehend. When the ancestors set foot in Terra Nova they had to survive in a harsh world among the ruins of the elven civilisation.
In the 1990s on Earth a magical anomaly caused half the population of the United States of America to be transported into a strange new world. Upon arriving there the people realized that any technology more advanced than late Middle Ages was not working. Many died from starvation, cold and diseases but in the end humans survived and created a new civilization.