Simplify the following text for a Grade 4 native English-speaking person.
Original: The Spanish league was originally set as a fixed unit of distance of 5,000 varas ( a Spanish yard ) , about 2.6 miles or 4.2 km .
Simplified: The Spanish League or legua was originally set as a fixed unit of distance of 5,000 varas ( 0.84 m each ) , about 4.2 km ( 2.6 miles ) .