Inside the Mission Concepción church at 6:30 p.m. Wednesday, if skies are clear, a beam of sunlight will illuminate the face of the Virgin Mary. At the exact same moment, another beam will illuminate a spot on the floor directly under the arched dome, at the heart of the cruciform, or cross-shaped, church.
This phenomenon is referred to as a double solar illumination, which can be appreciated for multiple reasons: its religious meaning, architectural ingenuity, historical significance, and cultural resonances underpinning the origins of San Antonio as a community.
Father David Garcia expects up to 200 visitors to crowd into the pews, aisles, and transepts of the small mission church to catch a glimpse of the phenomenon, but said each may have their own reasons for doing so.
“A couple hundred people in the church on that day, what it means to them, each one will have to tell you,” he said. “So I can’t tell you what it’s going to mean to you. I can tell you that it’s meant a lot to me,” he said of the seven years he has witnessed the occurrence. The illumination has presumably happened each year since the church was dedicated in 1755.
At 6:15 p.m., Garcia will give a short introduction, describing what to expect. From the original circular window in the rear balcony of the church, a beam of sunlight will arc across the north wall. At the same time, light from the high west window in the dome will play across the north transept wall.
For a very brief moment, the light beams will coalesce at the exact center of the room. Garcia encourages silence, he said. “Whatever God wants to tell us today, let’s just go quiet and be in the moment,” he said. The light beams then migrate away from the center of the church.
Garcia advises people to arrive early, as latecomers interrupt the proceedings by opening the west doors and letting too much sunlight into the church. The balcony windows aside the circular window are draped for the occasion, following the belief that the Franciscan Mission monks would have done the same in order to create the right atmosphere, he said.
The double solar illumination is one reason Mission Concepción is so historically important, said Rubén Mendoza, a professor of archaeology and social and behavioral sciences at California State University Monterey Bay. Mendoza is also a specialist in the history and significance of Spanish colonial-era missions.
Mission Concepción is regarded as one of the most well-preserved among its counterparts, recognized in 2015 by the San Antonio missions UNESCO World Heritage Site designation. Mendoza contributed to the effort with his scholarship and research, and hopes to achieve a similar designation for California’s mission sites.
“The mission church of Mission Concepción is one of the most sophisticated and well-designed examples of sacred geometry in the southwest,” Mendoza said.
There might be other such illuminations yet to be discovered in the Americas, Mendoza said, because during the colonial era of 1550-1700, more than 100,000 Spanish churches were built throughout the Southwest, Mexico, Central America, and South America.
This 150-year period was “construed by art historians as one of the greatest periods of construction activity in the world,” he said, and all were built with native labor.
But, Mendoza said, the indigenous communities were equal contributors to the construction, design ingenuity, and purpose of the missions.
“The reality is that we have more than sufficient documentation that as native communities built these churches, they came to embellish them” with their own symbols, which carried meanings important to the communities.
Each competed with other communities to build the most elaborate churches, and in turn, the Franciscans went to great lengths to accommodate indigenous beliefs into their liturgies, Mendoza said.
The friars also studied native languages and created glossaries, one reason some indigenous tongues still exist, he said.
Additionally, Jesus was then commonly referred to as Cristos Helios, he said, to identify Christ with the sun, which carried great significance to Native Americans, along with the moon, sky, and other natural forces. The Virgin Mary was associated with the moon, and is seen in the Mission Concepción depiction as standing astride the lunar orb, which appears to be eclipsing the sun.
Although the illuminations are sometimes construed as a colonialist strategy to attract what were then called “Indians” to Catholicism, Mendoza equates their religious significance to the architecture of Washington, D.C., which communicates an aura of power, and to other early examples of spiritual architecture like Machu Picchu or the pyramids of Egypt.
“The power realized in such monumental architecture is what we might construe as the cosmology and belief of a people,” he said.
Identifying himself as of American Indian descent, Mendoza described the native people of the colonial era as “embedding in the material world those things that were meaningful to them, and they continued to do that when they built the mission churches.”
Still, given the vagaries of weather, even moments of cosmological significance can fail to materialize.
Only once in his seven years as administrator of Mission Concepción have clouds obscured the sun during the illumination, which of course lessens the experience, Garcia said. As of Sunday afternoon, clear skies were predicted for Wednesday evening.