Castel Capuano is the second oldest of Naples' castles, and it wears its history like a suitcase wears travel stickers: layer on untidy layer. Norman king William I began it in the 1100s, Frederick II enlarged it a century later, and Angevin Queen Joanna extended it further. Its most memorable moment came in 1432, when courtier Sergianni Caracciolo was stabbed to death in his bedroom by four knights, allegedly on the queen's orders.

In 1540, Spanish viceroy Don Pedro de Toledo turned the castle into a courthouse, a role it kept for four centuries. The judges have since moved out, and the building now waits behind locked gates, destined to become a museum. Its name comes from the nearby Porta Capuana, the old gate to Capua.

VoiceMap's self-guided audio tours use the castle's shifting facade to trace Naples' revolving cast of rulers, Norman to Spanish, through the old centre.