Complex sentence: He is often referred to as the Duke of Bernay, part of his father's continental possessions, but this is a mistake based on the interpretation of an inscription on his tomb which was also intended for the Earl Beorn.
Split into simpler sentences: He is often referred to as the Duke of Bernay, part of his father's continental possessions. But this is a mistake based on the interpretation of an inscription on his tomb which was also intended for the Earl Beorn.