What is a triforium?
A triforium is the middle zone of the nave elevation in a church: a narrow passage within the thickness of the wall, or a blind arcade, between the main arcade below and the clerestory windows above. It is characteristic of Gothic architecture. The triforium sits at the level where the lean-to roof of the side aisle meets the nave wall. Behind that strip there is no room for windows, and that is exactly the zone the triforium fills.
Form and purpose
- Position: above the arcade arches into the aisle, below the clerestory windows.
- Form: in each bay, a row of small arches on slender colonnettes. Behind them runs a narrow wall passage, or the arches are set blind against the wall: a blind triforium.
- Purpose: it gives rhythm to the windowless band in front of the aisle roof. A walkable passage also allows maintenance and inspection at height.
- Development: in later Gothic the back wall was sometimes glazed, so the triforium lets light through and almost merges with the clerestory.
- Name: usually explained from Latin tri- (three) and foris (door, opening), after the three openings per bay often found. Two, four or more openings also occur.
Triforium or tribune?
A tribune (gallery) is a real storey over the full depth of the aisle. A triforium is much shallower and lies within the wall itself. High Gothic cathedrals such as Chartres show the classic three-part elevation: arcade, triforium, clerestory.
Practical tips
- Recognising it: look up from the nave. A continuous band of small arches just below the large windows is the triforium.
- During repairs: the passage behind the triforium is often the only access to gutters, roof timbers and windows. Keep it clear and safe to walk.
- Do not confuse it with a dwarf gallery: that runs along the outside of the building, the triforium inside.
Related terms
- Clerestory
- Arcade
- Side aisle
- Lean-to
- Gothic architecture
- Tribune
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