Keystone
The keystone or crown stone is the wedge stone at the highest point ("apex") of an arch , a dome or a rib vault .
to form
In the arch the keystone is always wedge-shaped, in the dome or in the vault, however, it is round, usually with ribs; it can also be designed as a knob or composed of several pieces in a ring, whereby the middle can also remain free ( opaion ). A special form is found in some vaults of the late Gothic to the "hanging keystone" or hanging knob (see: pendant vault ). Occasionally one can find keystones on Gothic vaults that are shaped as a ring open in the middle. In the medieval Passion Play, they were used so that statues of Christ could be pulled up on a rope through these openings in order to depict the Ascension of Christ in a scenic manner.
function
The keystone plays a decisive role in vault construction: only when it is inserted does the construction become self-supporting and the wooden falsework that was erected during construction can be removed.
Decor etc.
Due to its special importance and its central position, the keystone was often decorated with arches; the keystone of the Porta all'Arco , the only well-preserved gate of the city wall of Volterra from the time of the Etruscans , displays a head sculpture. Often the keystone bears the coat of arms or the initials of the builder, sometimes also the year of construction of the building. Rich decorations on the keystone of vaults were particularly common in Gothic architecture .
Examples
Side portal of the Cathedral of Syracuse / Italy
Keystone of the vaulted ceiling of the Justinuskirche in Frankfurt - Höchst
Vault stone of the middle yoke with the image of Christ , 14th century, Marienburg
Suspended in the Leonhardskirche in Frankfurt - old town
Apex stone with Prussian eagle coat of arms of the gate entrance of the Flensburger Bureau of Standards
Asymmetrical keystone in the south transept of the pilgrimage church of the painful mother of God (Bödingen) , 15th century
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See also
Individual evidence
- ↑ Gottfried Kiesow : Learning to see cultural history. Bonn: German Foundation for Monument Protection, Monuments Publ. Vol. 1, 2001, p. 70. Examples: Freiburg Minster , Predigerkirche Erfurt .
literature
- Entry keystone . In: Meyers Enzyklopädisches Lexikon . Bibliographical Institute, Mannheim / Vienna / Zurich 1973, Volume 21, p. 152.
- Wilfried Koch: architectural style ; Volume 2 - Castle and Palace. Special edition for Bassermann Verlag; Bertelsmann Lexikon Verlag, Gütersloh / Munich 1998, ISBN 3-8094-5007-3 , p. 482.
