0.1 Sunlight on Christ pulling on Adam’s arm in the Descent into Hell mural. Interior north wall of naos, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Gabriel-Dinu Herea) 2
1.1 Polar coordinate sun path chart made for the Dečani Monastery, medieval kingdom of Serbia (present-day Kosovo), but without temporal correction to the fourteenth century, with SunEarthTools.com 14
1.2 Sanctuary during Liturgy on 18 April 2017, katholikon of Dečani Monastery, medieval kingdom of Serbia (present-day Kosovo), 1327–1334 (source: Dragan Tanasijević and @Visoki Dečani Monastery, The Serbian Orthodox Church https://www.facebook.com/Decani.Manastir) 20
1.3 Dome on 20 August 2014, at 10:27 AM, katholikon of Dečani Monastery, medieval kingdom of Serbia, present day Kosovo, 1327–1334 (source: Anna Adashinskaya) 22
1.4 View to the founders’ burials in the southern bay, 22 October 2013, at 13:02 PM, katholikon of Dečani Monastery, medieval kingdom of Serbia (present-day Kosovo), 1327–1334 (source: Anna Adashinskaya) 23
1.5 Window slope on the southern wall, a seraph, katholikon of Dečani Monastery, medieval kingdom of Serbia (present-day Kosovo), 1327–1334 (source: Anna Adashinskaya) 25
1.6 View to the kibotion with Saint Stephan’s relics, 20 August 2014, at 12:04 PM, katholikon of Dečani Monastery, medieval kingdom of Serbia (present-day Kosovo) (source: Anna Adashinskaya) 27
1.7 Katholikon of Dečani Monastery, shelf adjoined to the marble barrier in the northern parekklesion, 1327–1334, medieval kingdom of Serbia (present-day Kosovo) (source: Anna Adashinskaya) 29
2.1 North-east view, Church of the Transfiguration of the Savior on Il’ina Street, Veliky Novgorod, 1378 (source: Olga Yunak) 38
2.2 Cross section looking north, floor plan at the street level, floor plan at the gallery level, Church of the Transfiguration of the Savior on Il’ina Street, Veliky Novgorod, 1378 (source: Mil’chik, Arkhitekturnoe nasledie, p. 267, modified) 42
2.3 View of the south-east corner of the chapel with representations of stylites (upper register), Church of the Transfiguration of the Savior on Il’ina Street, Veliky Novgorod, 1378 (source: Olga Yunak) 45
2.4 View from the floor level looking up in daylight, Church of the Transfiguration of the Savior on Il’ina Street, Veliky Novgorod, 1378 (source: Olga Yunak) 46
2.5 View of the central dome, Church of the Transfiguration of the Savior on Il’ina Street, Veliky Novgorod, 1378 (source: Olga Yunak) 52
3.1 View of interior: drum and east, south, west, and north vaults, Church of the Nativity of the Mother of God, Ferapontov Monastery, 1502 (source:
3.2 Dionisy, Savior with Forces [
3.3 Painting of the Great Martyr, warrior George, Church of the Nativity of the Mother of God, Ferapontov Monastery, 1502 (source: image courtesy The Museum of Dionisy’s Frescoes, Kirmuseum.org) 79
3.4 View of the south-western pillar with the Great Martyr, warrior Artemius on the right, Church of the Nativity of the Mother of God, Ferapontov Monastery, 1502 (source:
3.5 Interior view of the eastern central apse. Mother of God on the Throne with Archangels Michael and Gabriel, Church of the Nativity of the Mother of God, Ferapontov Monastery, 1502 (source: The Museum of Dionisy’s Frescoes, Kirmuseum.org) 81
3.6 Detail of the Great Martyr, warrior George, with remaining
4.1 Interior, south-eastern wall of the choir apse, sacrament niche made around 1425, Church of Saint Olaf in Tallinn (Reval) (source: Stanislav Stepaško, Tallinn) 94
4.2 Exterior, east wall of the choir with the sacrament niche’s opening, Church of Saint Mauritius in Haljala (Lääne-Viru County, Virumaa Region), niche dated to the second quarter of the fifteenth century; Interior, choir with the sacrament niche dated to the second quarter of the fifteenth century. Church of Saint Mauritius in Haljala (Lääne-Viru County, Virumaa Region) (source: Christofer Herrmann, 2005; Mart Viljus, Tallinn) 95
4.3 Interior, east wall of the choir with the sacrament niche, dated to the second quarter of the fifteenth century. Church of Saint James in Viru-Jaagupi (Lääne-Viru County, Virumaa Region) (source: Avo Sillasoo, Tallinn) 97
4.4 Interior, view into the choir with the sacrament niche, dated to the second quarter of the fifteenth century, Church of Saint John in Lüganuse (Ida-Viru County, Virumaa Region) (source: Mart Viljus, Tallinn) 98
4.5 Exterior, east wall of the choir with the sacrament niche’s opening, dating probably to the second quarter of the fifteenth century, Church of Saint Nicholas in Viru-Nigula (Lääne-Viru County, Virumaa Region); Exterior, sacrament niche’s opening, dating probably to the second quarter of the fifteenth century, Saint Nicholas in Viru-Nigula (Lääne-Viru County, Virumaa Region) (source: Mart Viljus, Tallinn; Christofer Herrmann, 2017) 99
4.6 Exterior, east wall of the choir with the sacrament niche’s opening, probably made toward the end of the fifteenth century, Church of Saint Michael in Juuru (Rapla County, Harjumaa Region) (source: Mart Viljus, Tallinn) 100
4.7 Interior, view into the choir with the sacrament niche, made probably toward the end of the fifteenth century, Church of Saint Michael in Juuru (Rapla County, Harjumaa Region); Interior, east wall of the choir, sacrament niche, made probably toward the end of the fifteenth century, Saint Michael in Juuru (Rapla County, Harjumaa Region) (source: Mart Viljus, Tallinn; The Department of Cultural Heritage and Conservation of Estonian Academy of Arts) 101
4.8 Exterior, east wall of the choir with the sacrament niche’s opening dating probably to the fifteenth century, Church of Saint Olaf on Vormsi. (Lääne County, Läänemaa Region); Interior, east wall of the choir with the sacrament niche, dating probably to the fifteenth century, Church of Saint Olaf on Vormsi (Lääne County, Läänemaa Region) (source: Christofer Herrmann, 2021; Mart Viljus, Tallinn) 102
4.9 Exterior, north-east view of the church with the choir and the sacrament niche’s opening, probably dating to the fifteenth century, Church of Saint Lawrence in Pühalepa (Hiiumaa County, Läänemaa Region); Exterior, the sacrament niche’s opening, probably dating to the fifteenth century, Church of Saint Lawrence in Pühalepa (Hiiumaa County, Läänemaa Region) (source: Christofer Herrmann, 2021; Christofer Herrmann, 2021) 103
4.10 Interior, view into the choir with the sacrament niche, probably made in the fifteenth century, Church of Saint Lawrence in Pühalepa (Hiiumaa County, Läänemaa Region) (source: Mart Viljus, Tallinn) 104
5.1 Plan of the Enkleistra complex. Enkleistra of Saint Neophytos, Cyprus. Drawing by Cyril Mango (source: Mango and Hawkins, “The Hermitage of St. Neophytos,” fig. D, letters added by the authors) 130
5.2 Deësis and Prophets. Cell, north wall and vault. Enkleistra of Saint Neophytos, Cyprus, twelfth century (source: Dimitris Minasidis and Maria Paschali) 130
5.3 Cross within three concentric rings. Cell, north wall. Enkleistra of Saint Neophytos, Cyprus, twelfth century (source: Dimitris Minasidis and Maria Paschali) 135
5.4 Christ Helkomenos and Crucifixion (above), recess of the Holy Cross between Archangels (below). Church of the Holy Cross, east wall. Enkleistra of Saint Neophytos, Cyprus, twelfth century (source: Dimitris Minasidis and Maria Paschali) 137
5.5 Descent from the Cross, Lamentation and Anastasis (above) and Saints Constantine and Helena (below). Church of the Holy Cross, east wall. Enkleistra of Saint Neophytos, Cyprus, twelfth century (source: Panayiotis Kyriakou) 139
5.6 Ascension and Neophytos between Archangels Michael and Gabriel. Chapel, upper part. Enkleistra of Saint Neophytos, Cyprus, twelfth century (source: Dimitris Minasidis and Maria Paschali) 145
6.1 Exterior view from south, Church of Hagios Panteleimon, Thessaloniki, thirteenth century (source: Iakovos Potamianos) 154
6.2 Interior view toward the south, nave, Church of Hagios Panteleimon, Thessaloniki, thirteenth century (source: Iakovos Potamianos) 156
6.3 Section, Church of Hagia Sophia, Thessaloniki, seventh century. The Pantokrator is only revealed when one crosses the door between narthex and nave (source: Kalligas, He Aisthetike tes Ellenikes) 158
6.4 Openings in the apse. (source: Iakovos Potamianos) 159
6.5 Sketch of dome window at the Megisti Lavra Monastery, Mount Athos, Greece. (source: Iakovos Potamianos) 160
6.6 Sketch of dome and its openings at Hagia Sophia, Constantinople, sixth century. (source: Iakovos Potamianos) 161
6.7 Metropolis Church, Mystras, Greece, thirteenth century. (source: Iakovos Potamianos) 161
6.8 Pillar of Light bonding Heaven and Earth called “The Spindle of Necessity” in the ‘Myth of Er’, in Plato’s Republic. Artwork by Edmond Lechevallier-Chevignard, nineteenth century (source: Wikimedia commons) 165
6.9 The Spindle of Necessity operates in a way similar to the swifter of the oar according to Plato, related to the movement of the Heaven around the Earth (source: Iakovos Potamianos) 166
6.10 “Jacob’s Ladder” in the Book of Genesis of the Old Testament in the original Luther Bibles of 1534 and 1545 (source: Wikimedia commons) 167
6.11 A shaft of Light in a cloudy sky. A phenomenon frequently encountered in Byzantine churches (source: Wikimedia Commons) 168
7.1 Hermit cell located in what is known as ‘Fuente de San Benito,’ San Pedro de Rocas, Galicia (modern Spain), sixth century (source: Petra Sacra Project: Natalia Figueiras Pimentel and Jorge López Quiroga) 176
7.2 Orientation and lighting of the rock-cut chapels in the rupestrian monastery of San Pedro de Rocas, Galicia (modern Spain), sixth century (source: Petra Sacra Project: Natalia Figueiras Pimentel and Jorge López Quiroga) 179
7.3 Location of the monastery in a mountainous and rocky landscape with an enormous symbolic load in a telluric and sacred sense, San Pedro de Rocas, Galicia (modern Spain), sixth century (source: Petra Sacra Project: Natalia Figueiras Pimentel and Jorge López Quiroga) 181
7.4 Location, orientation and lighting of the open-air rupestrian sanctuary, Christianized in Late Antiquity. San Pedro de Rocas, Galicia (modern Spain), sixth century (source: Petra Sacra Project: Natalia Figueiras Pimentel and Jorge López Quiroga) 183
7.5 Panel of the ‘engraved hands’ facing south. Iluminated on the Vernal equinox (VE) at sunset. Bronze Age. San Pedro de Rocas, Galicia (modern Spain), sixth century (source: Petra Sacra Project: Natalia Figueiras Pimentel and Jorge López Quiroga) 184
7.6 Light functions in the rupestrian monastery of San Pedro de Rocas, Galicia (modern Spain), sixth century (source: Petra Sacra Project: Natalia Figueiras Pimentel and Jorge López Quiroga) 186
7.7 Study of natural light, solstices and equinoxes in the rupestrian sanctuary, San Pedro de Rocas, Galicia (modern Spain), sixth century (source: Petra Sacra Project: Natalia Figueiras Pimentel and Jorge López Quiroga) 187
7.8 Example of the use of light in San Pedro de Rocas as an instrument of measurement and orientation in the construction of the different rupestrian elements, in this case stairs. Galicia (modern Spain), sixth century (source: Petra Sacra Project: Natalia Figueiras Pimentel and Jorge López Quiroga) 189
7.9 Longitudinal and transversal hagioscopes: illumination and privileged vision inside the rupestrian chapels, San Pedro de Rocas, Galicia (modern Spain), sixth century (source: Petra Sacra Project: Natalia Figueiras Pimentel and Jorge López Quiroga) 192
7.10 Privileged view of the sancta sanctorum (right paraecclesia) from the transverse hagioscope of the funerary paraecclesia (left chapel), San Pedro de Rocas, Galicia (modern Spain), sixth century (source: Petra Sacra Project: Natalia Figueiras Pimentel and Jorge López Quiroga) 193
8.1 Exterior, south and west side, Church of Sant’Ambrogio alla Rienna, Salerno, Italy (source: Andrea Mattiello) 204
8.2 Exterior, north and east side, Church of Sant’Ambrogio alla Rienna, Salerno, Italy (source: Andrea Mattiello) 204
8.3 Photogrammetric survey, floor plan, Church of Sant’Ambrogio alla Rienna, Salerno, Italy (source: Luca Borsa) 205
8.4 Apse façade, interior, Church of Sant’Ambrogio alla Rienna, Salerno, Italy (source: Luca Borsa) 206
8.5 North façade, interior, Church of Sant’Ambrogio alla Rienna, Salerno, Italy (source: Luca Borsa) 206
8.6 Apsidal window, frontal view, east façade, exterior and interior, apse, Church of Sant’Ambrogio alla Rienna, Salerno, Italy (source: Andrea Mattiello) 212–213
8.7 Interior of the church of Sant’Ambrogio alla Rienna with light simulation at sunrise on 19th of June, Salerno, Italy (source: Andrea Mattiello) 217
8.8 Interior of the church of Sant’Ambrogio alla Rienna with light simulation at sunrise on 4th of April, Salerno, Italy (source: Andrea Mattiello) 219
9.1 Exterior view from south-west, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Alice Isabella Sullivan) 229
9.2 Plan showing the small axial deviation toward the north, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Tudor-Cătălin Urcan) 231
9.3 Exterior view from the west, Church of the Holy Cross, Pătrăuți Monastery, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Alice Isabella Sullivan) 233
9.4 View of naos murals showing the visual parallels between the votive image and the Descent into Hell, view toward the west, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Petru Palamar) 235
9.5 Interior view of the pronaos murals showing the unique scene of the Cavalcade of the Holy Cross, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Petru Palamar) 235
9.6 Christ Pantokrator, interior mural, dome of pronaos, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Petru Palamar) 238
9.7 Prophet Isaiah, interior mural, drum of the steeple-like dome of the naos, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Gabriel-Dinu Herea) 239
9.8 Painted portrait of Saint Auxentius illuminated by a ray of sunlight entering through the south window of the naos, interior mural, north wall of the naos, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Gabriel-Dinu Herea) 240
9.9 Sunray substantiated by incense smoke falling on the Proskomide niche on the winter solstice. Sanctuary, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Gabriel-Dinu Herea) 242
9.10 Sunlight entering the church through the west entryway and aligning with the altar, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Gabriel-Dinu Herea) 244
9.11 Votive mural of John Stephen III and his family lit by the sunlight from the sanctuary window, interior mural, south wall of naos, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Gabriel-Dinu Herea) 245
9.12 Descent into Hell with sunlight on Christ’s left hand, interior mural, north wall of naos, Church of the Holy Cross, built 1487, Pătrăuți, Moldavia (modern Romania) (source: Gabriel-Dinu Herea) 246
10.1 The Church of the Mother of God at Studenica Monastery, Serbia, finished before 1208/9 (source: Dušan Danilović) 254
10.2 Floor plan and cross section, Church of the Mother of God at Studenica Monastery, Serbia, finished before 1208/9 (source: Jacob Gasper) 255
10.3 View toward the dome (photograph to the left and computer model to the right), Church of the Mother of God at Studenica Monastery, Serbia, finished before 1208/9 (source: Marko Pejić, Leslie Forehand, Debanjana Chatterjee, Jacob Gasper) 258
10.4 General view of the Studenica Monastery with the orthophoto marking of the skewing of the church approximately 6° from true west-east axis (source: Marko Pejić) 260
10.5 Interior illuminations for all windows of the church at Studenica Monastery in the year 1200. (source: Travis Yeager) 265
10.6 Interior illuminations for lower windows of the church at Studenica Monastery in the year 1200. (source: Travis Yeager) 266
10.7 Interior illuminations for dome windows of the church at Studenica Monastery in the year 1200. (source: Travis Yeager) 267
10.8 Interior illumination visualizations of the church at Studenica Monastery for the summer solstice and Christmas in the year 1200 (source: Leslie Forehand, Debanjana Chatterjee, Jacob Gasper) 268
10.9 Interior illumination visualizations of the church at Studenica Monastery for Christmas in the year 1200. (source: Leslie Forehand, Jacob Gasper, Debanjana Chatterjee) 269
10.10 Interior illumination visualizations of the church at Studenica Monastery for Christmas and Easter in the year 1200. (source: Leslie Forehand, Debanjana Chatterjee, Jacob Gasper) 271
10.11 Interior illumination visualizations of the church at Studenica Monastery and its dome for Christmas in the year 1200. (source: Leslie Forehand, Debanjana Chatterjee, Jacob Gasper) 272
11.1 Drawing of the topography of Studenica Monastery, Serbia, finished before 1208/9 (source: Ljiljana Čavić) 279
11.2 Environment of Studenica Monastery, Serbia, finished before 1208/9, drawing over photography (source: Ljiljana Čavić) 280
11.3 Natural Light Transformation, drawing (source: Ljiljana Čavić) 281
11.4 Orientation of the Church of the Mother of God at Studenica Monastery, Serbia, finished before 1208/9 (source: Ljiljana Čavić, drawing according to Radan Jovin, from Korać, Između Vizantije i zapada) 285
11.5 Architectural drawings, the Church of the Mother of God at Studenica Monastery, Serbia, finished before 1208/9 (source: Ljiljana Čavić, drawing according to Pokryshkin, from Pokryshkin and Polikarpova, Pravoslavna crkvena arhitektura) 290
12.1 Midwinter Solstice Illumination, Old Mission San Juan Bautista, San Juan Bautista, California (source: Rubén G. Mendoza) 303
12.2 Fresco mural of the Cristo Helios or Solar Christ from the convento at Mission Nuestra Señora de la Concepción, San Antonio, Texas (source: Rubén G. Mendoza) 305
12.3 Solstice Observers in Native California (source: Hudson, Lee, and Hedges, “Solstice Observers and Observatories,” redrawn by Emily Nisbet) 311
12.4 A treatise on the solar and lunar calendars for ecclesiastical computation by Don Pedro del Rio titled Compendio Metodico y Claro del Cómputo Eclesiástico Antiguo y Moderno: Segun Los Tres Afamados Sistemas, Juliano, Metónico y Gregoriano Adoptados por la Católica Iglesia para el Gobierno de Su Calendario, 1790 (source: Santa Barbara Mission Archives, 2016, 2022) 313
12.5 Table of Lunar concordances from Don Pedro del Rio, 1790, titled Tabla General, Extensa ó Dilatada de las Epactas, para Señalar Perpetuamente las Lunas Nuevas, 1790 (source: Santa Barbara Mission Archives, 2016, 2022) 314
12.6 Kalendarium Festorum or Feast Day Calendar from Old Mission San Juan Bautista, California (source: Rubén G. Mendoza) 315
12.7 Old Mission San Juan Bautista midwinter Solstice Illumination of Tabernacle, San Juan Bautista, California (source: Rubén G. Mendoza) 320
12.8 Mudéjar or Star of Bethlehem window at Mission San Carlos Borromeo, Carmel, California (source: Rubén G. Mendoza) 321
12.9 Midsummer Solstice illumination of the tabernacle at Mission San Carlos Borromeo, Carmel, California. The light pierces the nave with its fourteen stone arches, in a manner reminiscent of the fourteen stations of the Via Crucis, or Way of the Cross (source: Rubén G. Mendoza) 322
12.10 Plan of the Seven Churches at Mission San Carlos Borromeo, Carmel, California (source: after plans provided by Sir Richard Joseph Menn and based on the investigations of Sir Harry Downie, redrawn by Emily Nisbet, 2011) 323
12.11 The East or Main Façade of the Church of San Esteban del Rey, Acoma, New Mexico, dated to AD 1629 (source: Rubén G. Mendoza) 326
12.12 Historic American Buildings Survey Plan of San José de Laguna Mission Church, 1934 (source: Library of Congress) 327
12.13 Saint Francis de Assisi Feast Day illumination of the main altar tabernacle at Mission San José, California, on 4 October 2005 (source: Rubén G. Mendoza) 329
12.14 Diagram of kinematic liturgical iconography from Mission San Francisco de Asís, San Francisco, California. After the Historic American Buildings Survey (HABS) with modifications to indicate the trajectory of an August 2005 illumination (source: Rubén G. Mendoza) 330
12.15 Photo and diagram, kinematic liturgical schema of the patterning of solar geometry and liturgically significant illuminations spanning the period from 29 September through 19 October 2011 at Mission San Miguel Arcángel, San Miguel, California (source: Rubén G. Mendoza) 333
12.16 Solar geometry and the equinoctial illumination of the side altars of the Metropolitan Cathedral, aka: Catedral Metropolitana de la Asunción de la Santísima Virgen María a los cielos in Mexico City. (source: Rubén G. Mendoza) 336