International congress of byzantine studies belgrade, 22 27 august 2016

BYZANTINE ARCHITECTURE ‒ PART 2
Chairs: 
Charalambos Bakirtzis, Jelena Bogdanović
Iakovos Potamianos
, 
The Evolution of the Church Dome Lighting Method after Hagia Sophia of Istanbul
Charalambos Bakirtzis
– 
Ioannis Iliadis
, 
The Lighting in Two Byzantine Churches on Cyprus: 
The Panagia tis Asinou and the Panagia tou Arakos
Suna 
Çağaptay
, 
Solomoniac Myths: Reusing Solomon and His Temple in Byzantine Visualities
Sotiris Voyadjis
, 
The Katholikon of the Greatest Lavra Monastery in Athos Revisited
Nebojša Stanković
, 
Phialai on Mount Athos in the Middle Byzantine Period: 
Some Observations on Their Location, Setting, and Use
Jessica Varsallona
,
 
Notes on the History and Architecture of the Manastır Mescidi in Istanbul
Mar
é
va U
, 
Les fonctions des portes latérales des églises byzantines 
à la lumière des sources textuelles et matérielles (IV
e
-XV
e
siècle)

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Iakovos Potamianos
Aristotle University of Thessaloniki, Thessaloniki, Greece; 
[e-mail]
The Evolution of the Church Dome Lighting Method 
after Hagia Sophia of Istanbul
Byzantine church domes are paradoxically brighter than all surrounding surfaces. This interesting 
phenomenon has been investigated for the dome of Hagia Sophia of Istanbul, designed by Anthemius 
as a combination of two reflectors. The reflector designs are found in the architect’s own extant 
writings and must have been combined in a specific way in order to generate the luminous impression 
described by Procopius, Justinian’s court historian and eye-witness. This hypothesis has been largely 
proven in terms of geometrical, topographical and textual evidence in our previous papers. 
However, many other churches besides Hagia Sophia achieve a significant difference in 
luminosity from surrounding parts of the ceiling. Until now there has been no attempt to account 
for this impressive phenomenon. The question then becomes how do domes of lesser Byzantine 
church examples achieve luminosity while having a significantly different design to that of Hagia 
Sophia’s dome? Is there a method underlying this achievement? Any attempt to answer this question 
is particularly involved, since one does not deal with a single but with a multitude of buildings 
over various historical periods. Therefore, we have come to the decision to generate a model which 
would make use of parametric modeling based on some observations of actual Byzantine domes. We 
undertook the construction of a universal parametric dome model incorporating all variables that 
could possibly influence the luminous dome effect. With this model it became feasible to simulate 
a large number of actual test cases and account accurately for their light behavior, identifying 
beforehand the critical measurements needed in any church survey of each actual dome case. 
Accurate digital daylighting was employed to measure lux values and visualize the illuminance of 
the surfaces but, most importantly, by employing an animated particle system in order to visualize 
the travel path of light and reflections.
A dome may be made up of various parts. The drum, one or more curvatures placed above the 
drum, several openings varying from six to forty, pierced in the drum or in one of the curvatures 
in case the drum is eliminated. Additional variables are the proportional scale of dome plan to 
height, the openings proportions which depend on their number as well as the height of the drum 
and finally the varying slope and curvature of the window-sills, the main agents of all upward light 
reflection. These parameters were encoded in a user-configurable graphical interface that modifies 
the dome geometry within a 3D visualization environment. The user can then initiate the simulation 
and observe the behavior of light hitting the interior of any particular dome instance. Subsequently, 
the findings of the model are then related to images of actual domes from known monuments.

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