Complex sentence: One of the world's oldest breeds, it has been used for hundreds of years as a farm horse in Norway, and in modern times is popular for its generally god temperament and is used both as a harness horse and under saddle.
Split into simpler sentences: One of the world's oldest breeds, it has been used for hundreds of years as a farm horse in Norway, and in modern times is popular for its generally good temperament. It is used both as a harness horse and under saddle.