Insular art is the name given to the common style that developed in Britain and Ireland after the conversion of the Picts and the cultural assimilation of Pictish culture into that of the Scots and Angles, and which became highly influential in continental Europe, contributing to the development of Romanesque and Gothic styles. It can be seen in elaborate penannular brooches, often making extensive use of semi-precious stones, in the heavily carved high crosses found most frequently in the Highlands and Islands, but distributed across the country and particularly in the highly decorated illustrated manuscripts such as the Book of Kells, which may have been begun, or wholly created on Iona, the key location in Scotland for insular art. The finest era of the style was brought to an end by the disruption to monastic centres and aristocratic life by Viking raids in the late eighth century. Later elaborate metal work has survived in buried hoards such as the St Ninian's Isle Treasure and several finds from the Viking period.