There he sits, the 43-year-old, reasonably successful architect Jos Deltrap, on a bus to Italy, having departed from the Kruithuis in Den Bosch, capital of Dutch Noord-Brabant province, at 5 a.m. on June 3, 1952. It’s a journey in more than one sense for Jos. Just a few years after the war, the country is buzzing with reconstruction. He has a thriving design practice and is considered one of the notables of Deurne. But he wants more.

The monthly delivery of yet another block of social housing, a school, or a utility building—he’s frankly had enough. He’s been doing that for decades, but surely there must be more.

So in 1949, he began the Course in Ecclesiastical Architecture in Den Bosch. Set up by architect Nico van der Laan, with help from his older brother, the visionary Benedictine architect Dom Hans van der Laan, under the auspices of the diocese. A wave of bombed-out churches needs restoring, and more importantly, new churches must be designed and built—quickly! In the diocese alone, six per year. And the course must produce those architects, because when it comes to houses of worship, it’s about far more than just walls.

The question is: should these new churches stand in the great tradition, or should they reflect the spirit of the times? That’s why they’re going to Italy. Back to the source—to study early Christian architecture in Verona, Venice, Ravenna, and Rome. But also to look at modern church buildings erected during the interwar period in neutral Switzerland. And at pre-war Italian church architecture in Rome itself. In the prevailing rationalista style, many beautiful new churches are said to have been built. A new opportunity for the creative Jos. Fifty-five churches in three weeks, including a personal audience with Pope Pius XII. The tuxedo and gray gloves are packed at the bottom of the suitcase.

They’re traveling in an ultra-modern bus from the Geldersche Tramwegen, via Basel and Chiasso to Italy, returning through France. The bus is equipped with a toilet and kitchen—fewer stops needed—and has panoramic windows so you can see everything clearly.

The question is: should new churches stand in the great tradition, or should they reflect the spirit of the times?

About ten years ago, while looking at each other’s family photos, a dear friend of mine, designer Jelmer Zijlstra, pointed out the modernist St Willibrord’s Church that his grandfather, Jos Deltrap (1909–1973), had built in the village of Neerkant near Deurne. It was completed in 1957 [Figure 1]. I couldn’t believe my eyes. A generously wide, low box—very Mies van der Rohe—with a recessed, elevated barrel vault in the center, a slender freestanding bell tower, and to the right, an octagonal baptistery that resembled an imperial crown, mirrored on the left by a rectory. An octagon in the Low Countries—how extraordinary! All in radiant white, like an epiphany of the heavenly Jerusalem. And entirely made of concrete, inside and out.

The interior is a study in light. A fully glazed wall in the apse illuminates the altar from the south. Most striking on the outside is the entrance porch, spanning the full width of the church, with eight extremely slender columns that give the open façade a beautiful rhythm. As a classical archaeologist, I was immediately struck by its resemblance to the façade of my favorite basilica in the heart of Rome: Santa Maria in Cosmedin, built in the 5th century, located at the Forum Boarium near the Tiber Island [Figure 2].
In the ultra-romantic film Roman Holiday (1953), Gregory Peck shocks his date Audrey Hepburn by sticking his hand into the Bocca della Verità—the Roman manhole cover placed on the left side of the church’s porch (now a wildly popular TikTok destination). Legend has it (a Roma si dice che…) that the mouth will bite off the hand of anyone who lies—plenty of material for a romantic mini-episode [Figure 3].

As a classical archaeologist, I was immediately struck by the St. Willibrord’s Church resemblance to the façade of my favorite basilica in the heart of Rome: Santa Maria in Cosmedin, built in the 5th century.

But the resemblance between St Willibrord’s in Neerkant and the Cosmedin basilica in Rome remained, for me, one of those wild coincidences that seemed to carry no deeper meaning [Figure 4].

That resemblance stayed in the back of my mind—until last year, when a friend stepped down as secretary for dance and architecture at the Council for Culture. As a contribution to her liber amicorum, I decided to revisit that architectural echo. Encouraged by an enthusiastic response from modernism expert Prof. H.-J. Henket (and despite some dismissive reactions from other prominent architects), I dove in. At the same time, Jelmer’s family began taking an interest in his grandfather’s legacy. So we made the trip to Neerkant—over two hours by car from Amsterdam.

What we found was surprising. The church was still largely intact and stood freely in a spacious open setting. But it had been altered: dark red plywood cladding lined the roof edges, and the walls had been painted in a mix of mustard, brown, and khaki [Figure 5]. A conversation with the very kind sacristan (“we hold services here on Saturday evenings with about 20 faithful, in a cordoned-off corner because of the cold”) revealed that these changes happened shortly after completion, partly due to poor finishing quality.

That resemblance between the two churches stayed in the back of my mind. Encouraged by an enthusiastic response from modernism expert Prof. H.-J. Henket (and despite some dismissive reactions from other prominent architects), I dove in.

From the family archive, we learned that this church had been a daring feat—meticulously documented in photographs. But drawings and photos from a design five years earlier were radically different. In 1951, according to a dated caption (“these [postcards] were sold to benefit the new church”), Deltrap had envisioned a completely different structure: a stacked block with a pyramid roof, a separate sacristy, no tower or baptistery, and a stadium-like entrance with three doors behind a massive portal. More like the entrance to a football stadium than a church [Figure 6].

Again—what had happened? I was left with a barrel of questions, each more intriguing than the last.

I was left with a barrel of questions, each more intriguing than the last.

A Trail of Clues

I began with a simple Google search. Deltrap turned up quickly—not a celebrity, just a brief mention in the Nieuwe Instituut register, which maintains the canon of Dutch architecture. But when I searched “Rome” and “Deltrap,” I immediately found a photo of 25 young architects posing in front of the panoramic bus that took them to Rome in June 1952 [Figure 7]. How come? Because the “Bossche School,” the movement surrounding the Ecclesiastical Architecture Course led by Dom Hans van der Laan, later became world-famous (outside the Netherlands). His followers honored Van der Laan with meticulous documentation, now all online. Aha— so Deltrap was in Rome! But could there be more linking the design of St Willibrord’s in Neerkant, completed in 1956, to that Rome trip in 1952?
The Van der Laan Foundation, which preserves his legacy and archives, shared a relevant document with me. Hans van der Laan, his brother Nico, sister-in-law Els, and secretary Jeanne Daisy visited Rome together in 1955, some time after the excursion. In a diary fragment, Hans notes they attended Mass at the Cosmedin, which he found a disappointing mess. It was “not Roman,” beautiful in detail but lacking “that cool, pure harmony of the galleries.” No trace of a ‘plastic number’—his life’s work. But for me, it was clear: the church was known to the Van der Laans and may well have been visited in 1952.

Could there be more linking the design of St Willibrord’s in Neerkant, completed in 1956, to that Rome trip in 1952?

I let the matter rest for a while. But then Jelmer and I crossed paths with two researchers from Deurne: landscape historian Sil Bouwmans and historical geographer Luuk Keunen. In their spare time, they were updating a Wikipedia page on Deurne with information on the architectural heritage of their home village and had become deeply impressed by Deltrap. He had designed nearly half of Deurne between 1928 and 1969, plus many projects in the surrounding region. According to their catalogue, he worked on churches four times. Besides Neerkant, he designed a new façade for another St Willibrord’s Church, now in the hamlet of Vlierden around the same time—a rather peculiar wall placed in front of the old church [Figure 8].

Earlier, in 1950, Deltrap had built a neo-Romanesque church in Helenaveen. When we visited it, we were struck by its slavishly traditionalist design: aside from the mannerist spirelet it could have come straight from, say, AD 1150. A bit like the modern, deliberately nostalgic Catholic chapel at the OLVG hospital in Amsterdam. Yet it was so solidly built that 75 years later, it was still suitable for conversion into apartments [Figure 9].

Toward the end of his career, Deltrap also worked on the large Willibrord Church in Deurne itself. Between 1961 and 1964, he restored parts of it, including an aluminum entrance frame that earned him the eternal ire of many locals. They weren’t fans of modernity—even in small details.

To the Sources!

In this modest ecclesiastical corner of Deltrap’s vast oeuvre—430 projects, three-quarters of which were residential—St. Willibrord’s in Neerkant stands out. But where did he get the inspiration? As the saying goes, “If you don’t know what you’re looking for, you won’t find it.” But that doesn’t account for serendipity.

I wrote to the parish and diocesan archives to ask whether anything was known about the commissioning process. Such a striking design must have sparked discussion, or at least some prior consultation. What I received was a highly detailed construction dossier with drawings and calculations, plus a brief summary of correspondence between the architect, the diocese, and the pastor. There were complaints about cost overruns during construction and rejection of an earlier design that hadn’t accounted for the expected growth in parishioners. It had also lacked an explicit baptistery. All this came via diocesan archivist Jef van Gils—but I never saw the original documents. There was also mention of the church’s deplorable condition just twenty years after completion, and a confirmation of restoration and repainting work. Together, these costs amounted to a quarter of the original construction budget. But no explanation was given for the design choices—neither for the initial build nor the later repairs.

So I returned to the source: the Rome trip kept haunting me. That starting point led me to the regional archive in Den Bosch (BHIC), where I found documents in the file of Architectenbureau Van der Laan, which had led the ecclesiastical architecture course and organized the 1952 Italy trip. I uncovered hundreds of documents from the Mgr. van Heukelum Foundation, which oversaw the course and the excursion. These revealed that the educational portion of the trip began in Switzerland, and from the Italian border onward, the bus visited as many early Christian churches as possible.

The Rome stay lasted four days and included a wide range of churches, organized chronologically: Early Christian and Carolingian, Medieval, and Baroque. Fifteen cities and three periods were evenly divided among the participants. The “older and Carolingian basilicas” were assigned to Deltrap and two colleagues, Schijvens and Donker. And—eureka!—on the handwritten and later typed longlist of fourteen Roman churches was… Santa Maria in Cosmedin. There was also a list of ten briefly described modern churches in Switzerland (Basel, Lucerne, Zurich: “some concrete churches”), one in Milan, and two in Rome. On one version of the final church list, the Roman churches were marked in red. The Cosmedin was both underlined and crossed out, with a handwritten note: “Colosseum, Forum, Palatine, Capitol [sic], S.M. in Aracoeli.” Was the Cosmedin basilica skipped in favor of the major Roman monuments nearby? We’ll never know.

And—eureka!—on the handwritten and later typed longlist of fourteen Roman churches was… Santa Maria in Cosmedin.

Still, my conclusion was clear: yes, the excursionists had seen the Cosmedin basilica and very likely also visited it. And Deltrap had been one of the specialists assigned to research churches from the late and post-antique periods. A curious detail: although Cosmedin dates from the 5th century and was dedicated to the Greek Orthodox rite in the 8th century—thus pre-Carolingian—it was categorized as “medieval” in the excursion documents.

With some time left in the archive, I peeked into another folder in the same box: the 1951–1952 course year records. My first professional archive visit—possibly my last—so I seized the moment. Amid the sleep-inducing documentation of that year (endless budgets, attendance lists, correspondence, and board meeting minutes), I found half a dozen sheets of tracing paper. Torn from a roll, covered in pencil sketches, labeled “miscellaneous.” I laid them out and saw study sketches and doodles. One showed a schematic façade with seven openings and a strange table on the left. Signed “J. Deltrap” [Figure 10]. Bingo. And didn’t that table resemble the Bocca della Verità?

Another tracing sheet, with an obscured signature, showed basilica floor plans and the projection of an octagonal building on a modular grid [Figure 11]. On the same sheet—perhaps in the same hand—were perspective sketches of column and arch galleries, including a seven-arched one [Figure 12]. My goodness—if this wasn’t a smoking gun.

There was more. Among the course records was a note listing requirements for the final project—“Project 1952.” It read: “A study design for a church in a given location, seating capacity 800,” with drawings, details, perspectives, and a “study model in clay, plasticine, or wood, scale 1:500.” The date on the photo of Deltrap’s clay model for Neerkant was 1951—before the excursion, which took place in June 1952. So the inspiration for the executed retro-modernist hybrid in Neerkant must have come after 1951.

That Deltrap had ultra-modern ideas in mind became clear later. At home, I reviewed the list of interwar churches featured on the excursion. Among them was the S. Ippolito Martire church in Rome’s Nomentana district, built in 1934 [Figure 13]. Its blind façade by Italian master C. Busiri Vici is clearly a nod to the venerable S. Maria in Aracoeli basilica, firmly within the rationalista style… and it appears almost identically in the façade Deltrap designed for the Vlierden St. Willibrord’s—the same year Neerkant was completed.

There are more postwar Catholic churches in southern Netherlands inspired by modernist examples from southern Europe. Just an hour’s bike ride from Neerkant, in Overloon, stands the HH. Theobaldus en Antonius by architect Jan Strik, now a national monument. In a second BHIC file, I discovered that Strik was one of Deltrap’s four classmates in that year’s ecclesiastical architecture course. He even traveled to Switzerland with the pastor to seek inspiration for his new church in Overloon (S. Franziskus by Fritz Metzger in Basel-Riehen, 1949–1950). Parallel paths: the same year Deltrap completed his futuristic church in Neerkant, a sister building was inaugurated in neighboring Overloon—with the same southern light on the altar, a separate campanile, and a mirrored layout of rectory and octagonal baptistery.

On the return trip from Rome in the Geldersche Transbus, Jos Deltrap is brimming with impressions and ideas. Will he dare to take a stand in the heated debate between tradition and innovation? What does he truly believe? What can modern church architects offer that surpasses what was already so brilliantly conceived and built long ago? He’s unsure about the durability of concrete—but eager to experiment. Maybe he should revisit that final project from last winter. Combine old and new. Create a sustainable hybrid: respectful of tradition, but built with the materials of the future.

—

I should like here to express my gratitude to Wibo Quist (TUD), Hubert-Jan Henket, BHIC, Ward Klinkberg (Archives Eindhoven), Jef van Gils (Episcopal Archives Den Bosch), RK parish Deurne, John Deltrap, Meike Deltrap, Jelmer Zijlstra, Sil Bouwmans, Luuk Keunen, Chris van Esterik, Annemiek Sterk, Allen Jaeger, Ad Cosijn, Ton Gielens, Julie Oldenburger (Van der Laan Foundation), Leo Dubbelaar (Cuypersgenootschap Foundation). At the recommendation of the Cuypersgenootschap Foundation, the municipality of Deurne decided on November 11, 2014 to place the St. Willibrord’s Church in Neerkant on its list of monuments.

Images

• Figure 1. Aerial view of St. Willibrord’s Church in Neerkant, 1957.
• Figure 2. Basilica of Santa Maria in Cosmedin (initial construction 5th century AD), Rome.
• Figure 3. Screenshot from the trailer of A Roman Holiday (1953) featuring Gregory Peck and Audrey Hepburn. Photo: Wikimedia Commons.
• Figure 4. Overlay of St Willibrord’s in Neerkant and the Cosmedin basilica in Rome.
• Figure 5. St. Willibrord’s Church in Neerkant, 2024. Photo by the author.
• Figure 6. Deltrap’s first design for St. Willibrord’s Church in Neerkant (1951). Clay model and axonometric perspective drawing. Photo: Deltrap family.
• Figure 7. Students and instructors – participants in the Italy trip of the Ecclesiastical Architecture Course, June 1952. Deltrap is fourth from the left. Photo: BHIC.
• Figure 8. Façade of St. Willibrord’s Church in Vlierden (1955). Photo: Wikipedia.
• Figure 9. Postcard of St. Willibrord’s Church in Helenaveen, presumably from the 1950s. Collection: Municipality of Deurne; photo: Wikipedia.
• Figure 10. Sketches signed “J. Deltrap” from the 1951–1952 annual archive of the Ecclesiastical Architecture Course.
• Figure 11. Unsigned sketches from the 1951–1952 annual archive of the Ecclesiastical Architecture Course.
• Figure 12. Unsigned sketches from the 1951–1952 annual archive of the Ecclesiastical Architecture Course.
• Figure 13. Front view of the church of Sant’Ippolito Martire, Rome (1934). Date unknown. Photo: Wikimedia Commons.