<P> Integrated with the lofty verticals of Gothic cathedrals and parish churches, glass designs became more daring . The circular form, or rose window, developed in France from relatively simple windows with openings pierced through slabs of thin stone to wheel windows, as exemplified by the west front of Chartres Cathedral, and ultimately to designs of enormous complexity, the tracery being drafted from hundreds of different points, such as those at Sainte - Chapelle, Paris and the "Bishop's Eye" at Lincoln Cathedral . </P> <P> While stained glass was widely manufactured, Chartres was the greatest centre of stained glass manufacture, producing glass of unrivalled quality . </P> <Ul> <Li> Medieval glass in France </Li> <Li> <P> Detail of a 13th - century window from Chartres Cathedral </P> </Li> <Li> <P> Charlemagne from a Romanesque window in Strasbourg Cathedral </P> </Li> <Li> <P> The Crucifixion window of Poitiers Cathedral </P> </Li> <Li> <P> Late Gothic Tree of Jesse window from Evreux Cathedral </P> </Li> <Li> <P> The South Transept windows from Chartres Cathedral </P> </Li> </Ul> <Li> Medieval glass in France </Li>

In stained glass pieces of glass are joined together with narrow lead strips called