Built by the Dutch East India Company between 1666 and 1679, the Castle is the oldest building in South Africa. In 1682, the gated entry replaced the old entrance towards the sea. A bell tower, situated over the main entrance, was built in 1684 — the original bell, the oldest in South Africa, was cast in Amsterdam in 1697 by Claude Frémy and weighs just over 300 kilograms. It was used to announce time, as well as warning citizens in case of danger, since it could be heard 10 kilometers away.