A nearly completed gypsum window sits at the center of the workshop beside al-Aqsa mosque, the third holiest site in Islam (all photos by the author for Hyperallergic)

Walking around Jerusalem’s iconic, gleaming Dome of the Rock with Bassam Hallak is a history lesson, architecture class, and news brief all rolled into one whirlwind tour session.

But Hallak isn’t a tour guide. He’s the chief architect at the Haram al-Sharif, as it is known in the Islamic tradition, which houses the Dome of the Rock and al-Aqsa mosque, the third-holiest site in Islam. He’s also a very busy man, responsible for the 144-acre site’s upkeep, conservation, restoration, and decoration. On this particular morning, he’s checking in at the Haram’s most hidden artistic treasure: its gypsum-window workshop.

A view of the Dome of the Rock from the chief architect’s office at the Haram al-Sharif

The chief architect’s office is located just beside the Dome of the Rock, in a small, unassuming stone building.

On the stroll from his cluttered office to the southern end of the Haram, Hallak weaves around a large group of worshippers, then a gaggle of American tourists, and then stops to discuss bringing in a new supply of paint with the Israeli police who patrol the grounds. In the shadow of the solemn and stately al-Aqsa mosque, a line of unassuming, tin-roofed sheds is barely noticed by the hundreds of visitors milling about the holy site.

The inside of the chief architect’s office charts the visual and architectural history of the Haram al-Sharif, crammed full of tiles, calligraphy, photographs and ephemera.

The gypsum window workshop is housed in an unassuming tin-roofed building at the southern end of the sanctuary.

“We’re here, we’re at the gypsum workshop!” Hallak assures me as we walk up to the shed on the left. From the outside, it doesn’t look like it could hold much more than a few wheelbarrows. But inside, a team of eight men is working to preserve a particularly Islamic tradition of stained-glass-window making, using techniques that date back hundreds of years.

Inside the gypsum window workshop, a team of eight men navigate the tiny space, a labyrinth of scaffolding, wooden frames, and finished pieces.

“We work on different kinds of gypsum windows, like this one,” Hallak says as we wedge ourselves into the small studio space, filled with iron support rods. In front of us is a mammoth circular rose window with an intricate floral design in a mix of blues, reds, and oranges. “In al-Aqsa mosque, we have around 250 windows, all different sizes. But mostly they are about a width of 90 cm and length around 1.5 meters. Inside the Dome of the Rock we have around 100, and the problem is we have only one specialist on this work.”

Each window starts out on paper; when fully planned, the intricate Islamic designs are then transferred to the blank gypsum with charcoal and pencil.

Each member of the team specializes in different parts of the window-making process. Here, the gypsum, a type of carve-able plaster, is in the early stages of design-carving.

Each window frame is sized and created onsite and then filled with the gypsum plaster.

As if on cue, a man in chinos and a button-down shirt walks through the workshop door. “The others work with him, but he’s the number one,” Hallak says, pointing to the new arrival. Bashir, he explains, has inherited his role as head craftsman from his father, who learned from Bashir’s grandfather. “All of this gypsum is handwork,” Hallak says proudly. “We need about five or six months for each window.”

The workshop is made up of two workrooms, and we follow Bashir into the first, where the process begins. After Hallak decides which of the windows need restoration or replacement, measurements are taken and a new wooden frame is made to fit the space exactly. The frame is then filled with a special type of gypsum. In its natural state, gypsum is a mineral compound used as the main ingredient in different types of plaster. Here, the gypsum mixture is soft enough to be carved by sharp hand tools but sturdy enough to bear the weight of the glass.

Bashir is the most senior gypsum specialist in the workshop. He inherited the position from his father, who learned the craft from Bashir’s grandfather.

The lights in the workshop illuminate the initial rough cuts in an intricate floral pattern.

The carving process is painstakingly precise. A large design plan is mapped out in pencil, then transferred to the gypsum with charcoal. Today, two large arched windows are in the initial stages of carving — plaster litters the floor, and sketches are pinned to the frames for more precise freehand design. The floral and geometric patterns that are prevalent in many traditional Islamic tile designs also decorate the stained-glass windows. When asked how many designs they use, Hallak and Bashir laugh. “Too many!” they say.

Chisels, lathes, and other hand tools are strewn about the workshop, never far from a hot cup of sage tea.

Chief architect Bassam Hallak stands beside the Dome of the Rock. He says that one of the biggest misconceptions about the Haram is that “most people think that the Dome of the Rock is al-Aqsa!”

Hallak makes sure to point out an older stained-glass window from the mid-20th century hanging on the wall. “See how thick?” he asks, pointing at the back of the window, which would have been seen from the inside of the building. Bashir has modernized and perfected the carving technique so that the interior side of the window is clearly considered and very delicate.

The interior side of the window is also angled downward, and the glass appears inset, which adds another level of complexity. “The carving is at a 45-degree angle; it is not straight,” Hallak says. “All these windows, we put them at high levels. We do it at 45 degrees to permit sunlight to enter, because they are so high on the wall.”

We shuffle carefully into the second room, where the glass is applied to the gypsum. Bashir consults with one of his workers, who is measuring the spaces on the exterior side of the window. A sand-like dusting of multicolored glass decorates the floor like glitter. In this room, three men are busy tracing the small negative spaces in the design onto little pieces of glass, which they then cut by hand with knives.

After the design has been fully carved into the gypsum, the window frame moves into the room where glass is applied.

Glass shards are carved by hand to fit the design gaps exactly, then adhered with wet plaster.

One of the workshop team holds a shard of blue glass before a window that is nearly complete.

They work methodically, with bright spotlights shining through the colored windows, and then mix a thinner gypsum, painted to fix the glass shards to the exterior side of the window. When the gypsum dries, the result is a slightly bumpy flat surface that looks nothing like the other side — it’s a bit messier and a bit richer in color due to the fact that there are no angled protruding lines — but it’s no less beautiful.

The walls of the workshop are filled with Arabic calligraphy, design templates, and old frames.

The back of the gypsum window, which is seen from the interior, is more delicate than the front. The neatly angled gypsum is scaled to light the interior of the mosques from their high positions on the walls.

As we leave the workshop, Hallak is called over to the side entrance of al-Aqsa, where prayers are just about to begin. I comment that it must be difficult to oversee the preservation of one of the holiest sites in Islam with so many visitors around all the time. “It’s not difficult!” he exclaims happily, explaining that his team of 70 workers are guaranteed a break around midday prayers, when the site fills with worshippers.

The plaster is applied to the glass on the front of the window. This side, which functions as the exterior of the window, is a bit less finished but still achieves a grand effect from high on the mosque walls.

Back in his office, Hallak tells me he is keen to retire soon but has no idea how he will — he simply has too much to do. He’s 60 and has overseen the Haram for the past 38 years. As he rattles off his to-do list, filled with delicate dome restoration and window installations, it’s hard to imagine someone qualified enough to replace him. “Some days I leave and my head is like this,” he jokes, hands shaking around his head — a man with too much to worry about. “It’s a tough job, but I do like my work.”

The gypsum windows, in situ, at al-Aqsa mosque.

Mary Pelletier is an American writer and art historian specializing in early Middle Eastern photography. She is based in Jerusalem.