Complex sentence: In 1284, some time after the death of his next-elder brother Eric of Småland, and during the reign of Magnus, Benedict was made Duke of Finland, the first known holder of that title and appanage.
Split into simpler sentences: In 1284, some time after the death of his next-elder brother Eric of Småland, and during the reign of Magnus, Benedict was made Duke of Finland. He was the first known holder of that title and appanage.