Also known as the Dark Ages and the Age of the Saints and spanning the period between the breakdown of Roman rule and the Norman Conquest. Christianity spread and the kingdoms and language of Wales emerged at this time, although they came under pressure from Irish, Viking and Anglo-Saxon groups. Little is known of settlement although some Iron Age hillforts were reoccupied. The most visible and iconic remains are carved stone memorials to individuals, with writing in Latin and the Irish Ogham alphabet, and the slightly later cross-carved stones and stone sculpture.