List of ancient spiral stairs

The spiral stair is a type of stairway which, due to its complex helical structure, has been introduced relatively late into architecture.

Although the oldest example dates back to the 5th century BC,[1] it was only in the wake of the influential design of the Trajan's Column that this space-saving new type permanently caught hold in ancient Roman architecture.

[2] Apart from the triumphal columns in the imperial cities of Rome and Constantinople, other types of buildings such as temples, thermae, basilicas and tombs were also fitted with spiral stairways.

[2] Their notable absence in the towers of the Aurelian Wall indicates that they did not yet figure prominently in Roman military engineering.

[2] By late antiquity, separate stair towers were constructed adjacent to the main buildings, like in the Basilica of San Vitale.