‘Unlike other monks, Cistercians wore plain, undyed wool – for which reason they were known as the ‘White Monks’. The return to heroic monasticism meant that they ate only the coarsest wheat bread, and were ordered to avoid coloured glass in the chapel, and gold and silver on the altar.
And they were not allowed to wear underpants. St Benedict had not mentioned them in his list of permitted clothing for monks, so the Cistercians would have no truck with the evil things – much to the amusement of a number of their contemporaries. Some called it ‘bare-bottomed piety’ and Walter Map, the twelfth-century author, wit and foe of Cistercians, suggested they shunned underpants ‘to preserve coolness in that part of the body lest sudden heats provoke unchastity’.’
– Jones. T., Ereira. A. 2004. Terry Jones’ Medieval Lives London, Great Britain: BBC Books (2005) p. 99