Complex sentence: In the same year the sailing expedition of Christopher Columbus resulted in what is usually claimed to be the first European sighting of the New World, although Leif Ericson is often regarded as the first European to land in the New World, 500 years before Christopher Columbus.
Split into simpler sentences: In the same year the sailing expedition of Christopher Columbus became the first European sighting of the New World. Although Leif Ericson is often regarded to be the first European to land in the New World, 500 years before Christopher Columbus.