Simplify the following text for a Grade 7 native English-speaking person.
Original: According to the Finnesburg Fragment , the Danish prince Hnaef came with sixty followers to visit and spent the winter at the Finnburg , the fort of his brother-in-law Finn , king of the Frisians .
Simplified: According to the Finnesburg Fragment , the Danish prince Hnaef came with sixty followers to visit and spent the winter at the Finnburg . Finnburg was the fort of his brother-in-law Finn , king of the Frisians .