<P> In 1757, a number of changes were made to the interior to increase the visibility of the Mass, in accordance with changing religious customs . The jubé (choir screen) that separated the liturgical choir from the nave was torn down and the present stalls built (some of the magnificent sculpture from this screen was later found buried underneath the paving and preserved, though it is not on public display). At the same time, some of the stained glass in the clerestory was removed and replaced with grisaille windows, greatly increasing the illumination of the High Altar . </P> <P> In 1836, the old lead - covered roof, with its complex structure of timber supports (known as' the forest') was destroyed by fire . It was replaced with a copper - clad roof supported by a network of cast iron ribs, known as the Charpente de fer . At the time, the framework over the crossing had the largest span of any iron framed construction in Europe . </P> <P> The cathedral was damaged in the French Revolution when a mob began to destroy the sculpture on the north porch . This is one of the few occasions on which the anti-religious fervour was stopped by the townfolk . The Revolutionary Committee decided to destroy the cathedral via explosives, and asked a local architect to organise it . He saved the building by pointing out that the vast amount of rubble from the demolished building would so clog the streets it would take years to clear away . However, when metal was needed for the army the brass plaque in the centre of the labyrinth was removed and melted down; our only record of what was on the plaque was Felibien's description . </P> <P> The Cathedral of Chartres was therefore neither destroyed nor looted during the French Revolution and the numerous restorations have not diminished its reputation as a triumph of Gothic art . The cathedral has been fortunate in being spared the damage suffered by so many during the Wars of Religion and the Revolution, though the lead roof was removed to make bullets and the Directorium threatened to destroy the building as its upkeep, without a roof, had become too onerous . </P>

This is the large central space of a romanesque or gothic cathedral. quizlet