Complex sentence: Hero Oomkens von Esens (c.1455--1522) was a Frisian nobleman, the Earl of Harlingerland, who inherited the title upon the death of his father, Sibet Attena von Esens, in 1473.
Split into simpler sentences: Hero Oomkens von Esens (c.1455--1522) was a Frisian nobleman, the Earl of Harlingerland. He inherited the title upon the death of his father, Sibet Attena von Esens, in 1473.