During the industrial revolution slate from Wales was exported all over
the world. The slate communities of North Wales were close-knit, particularly at times of conflict. During the great strike of 1900-3 at Penrhyn Quarry, the hardship was such that some men were forced to return to work - therefore becoming know as Bradwyr ['Traitors']. Cards like these were placed in windows to show no 'traitor' lived there. The Penrhyn lockout was one of the longest in British labour history.