
It's the highest piece of coastline on the south coast (626 feet high), and offers views for miles, which would have been important around 1000 years ago. The first Viking raid on England (which wasn't really England then, since it was a collection of kingdoms like Mercia, Wessex, etc) was in the 8th century on the Dorset coast, so they probably would have used the high point to watch for Vikings coming across the "narrow seas."
If you head down the western slope, there's a stream called St. Gabriel's Water, and a little upstream are the ruins of the 13th century St. Gabriel's church. The water goes back into the sea at a secluded beach that was used by smugglers for centuries to bring in contraband goods.
Completely unrelated, other than the viking connection to Dorset, apparently Viking warriors used to file their teeth. To look tough. Or have dental bling. According to skeletons found in a Dorset grave, these guys filed their teeth to have horizontal marks, possibly to scare their enemies. It just sounds painful to me.