Steps have been taken to better, more straightforwardly, understand the stair or vice. Read all about it, in:
“The Spiral Stair or Vice: Its Origins, Role and Meaning in Medieval Stone Castles,” Charles Ryder, doctoral thesis, University of Liverpool, 2014.
Ryder writes: “This thesis addresses a neglected area of castles studies – the spiral stair. It studies the origins, evolution, placing, structure, role, significance and meaning of spiral stairs in medieval stone castles between 1066 and 1500, so covering the rise, zenith and decline of the castle in England and Wales. Although focussed upon England and Wales, it has a wider geographical spread across Ireland, Scotland, Europe, the Middle East and Japan with particular regard to castles and on even wider when searching for the origins of the spiral stair, encompassing the whole globe.”