Like Pilsdon Pen this early Iron Age hillfort with a single ditch and bank (rampart) also has a rich and varied past. Between 1709 and 1947 an annual fair was held here on the Wednesday before the feast of St John the Baptist on June 24. You can still see the imprint of the fair house and the low banks marking the livestock pens or market stalls. During the 18th century there was also a horse-racing track built as part of the fair. This is still visible today to the southwest of the hillfort straddling the Wessex Ridgeway.
In 1806, in response to the threat of a Napoleonic invasion from France, an admiralty telegraph station was erected here at Lambert's Castle. It was part of a chain of signal posts from the main fleet stationed in Plymouth to the Admiralty in London. Messages were sent using a system of six shutters mounted on the roof of a signal building. In good conditions a message could be relayed from Plymouth to the Admiralty in 20 minutes. By the end of the Napoleonic war in 1816 this system was proved unreliable in strong winds and was replaced by the two-arm semaphore system and later, the electric telegraph.