CRYPTOPORTICUS

a covered gallery that was a characteristic feature of the ancient Roman palazzo. It was usually designed to provide shade and a cool place for walking. Such a gallery was part of the Roman emperor Diocletian's Palace at Spalatro (Split, Croatia) and the House of the Cryptoporticus in Pompeii. Sometimes the cryptoporticus served a dual purpose; a vaulted passage, partly decorated with fine stucco, was built by the emperor Nero in about AD 65, primarily to connect his palace, the so-called Golden House of Nero, with other imperial palaces on the Palatine Hill.