Date: Wed, 12 Jul 2006
I really want to know about polyhedra in/on churches.
(a) It is very common in Hungary that the peak of the tower of protestant church buildings (mainly Calvinist, but sometimes Lutheran as well) is decorated with a star polyhedron symbolizing the star of Bethlehem (or a mace or both). I would like to know whether there is something similar in other countries.
REMARK. This kind of decoration spread after 1781 when Emperor Joseph II by decree allowed protestants free practice of their religion. (Maybe the star symbol goes back to the time of anti-protestantism and religion war when this object could be considered as a weapon as well, but no intact protestant churches remained from that period, at least I do not know any evidence.) Hungarian Calvinists never put a cross on the top of their churches (they have a star or a cock), but the Lutherans do.
(b) I know that in Rome, the church Sant Ivo alla Sapienza, the dome and the facade of the church San Andrea della Valle, the dome of the Sacresty of St. Peter's catherdal, and many of the Egyptian obelisks are decorated with star polyhedra. I would like to know whether there are other exaples of star polyhedra in Rome and in other places (cities) in Italy.
REMARK. As far as I know, occurrence of star polyhedra in Rome is a consequence of the fact that many popes had stars in their coat of arms. It was a natural intention that if they wanted to represent this 2-dimensional heraldic symbol in 3-space, star polyhedra were used. Up to my knowledge, the first examples are due to Pope Sixtus V (1585-90). Many obeliscs, including that in St Peter's Square are decorated with star-polyhedron-looking objects. In fact they are not polyhedra. They are composed of two equal planar eight-pointed star polygons in a way that one is standing on a point in a vertical plane and the other is rotated by 90 degrees about the vertical axis passing through the supporting point. This object is rather a "nolid" according to Alan Holden's terminology. Later examples are real polyhedra, for instance at the church San Andrea della Valle and the obelisc in Piazza di S. Maria sopra Minerva (under Pope Alexander VII, 1655-67), the obelisk in Piazza della Rotonda (under Pope Clemens XI, 1700-21), as well as the Sacresty of St Peter's (under Pope Pius VI, 1775-99). These are elevated polyhedra, or star polyhedra with extended points.
(c) I know some church monuments in England, decorated with polyhedra: in Salisbury Cathedral, Wimbourne St Giles Parish Church, St Lowrence Church in Reading, Merton College Chapel Oxford. I know also the famous pavement mosaic attributed to P. Uccello, Basilica of St Mark in Venice, and Fra Giovanni's intarsia in the Monastery of Monte Olivetto Maggiore (near Siena) and in the church of Santa Maria in Organo, Verona. I would like to know whether there exist further polyhedra and polyhedral representations in churches.