Sala delle Asse: Leonardo’s Painted Room at Sforza Castle

Of everything inside Sforza Castle, the Sala delle Asse is the room art lovers travel for — and the one most likely to disappoint someone who assumes it will simply be open. It is a genuine Leonardo da Vinci work in situ, not a copy or a reconstruction, but decades of damage, over-restoration, and ongoing conservation mean the room’s availability changes often. This guide explains what the Sala delle Asse actually is, what survives on its walls and ceiling, why it keeps closing, and how to find out whether you can see it on the day you visit.

What the Sala delle Asse Is

The Sala delle Asse (“Room of the Wooden Boards,” named for the timber paneling that once lined its walls) sits at ground level in the Torre della Rocchetta, the inner keep of Sforza Castle. Ludovico Sforza, known as “il Moro,” commissioned Leonardo da Vinci to decorate the vaulted ceiling around 1498, near the end of Leonardo’s first long stay in Milan and shortly before the fall of Sforza rule to the French. It was one of several decorative commissions Leonardo carried out for the Sforza court alongside his better-known work on the Last Supper at nearby Santa Maria delle Grazie.

Rather than a conventional fresco of figures or scenes, Leonardo turned the vault into an illusion: the room reads as if it were open to the sky, with the actual stone ribs of the vault absorbed into a dense, painted grove of trees. It is one of the few surviving decorative interiors that can be attributed directly to Leonardo, which is what makes it significant enough to draw visitors even though — as this guide is honest about — it is far from guaranteed to be open or fully visible when you arrive.

The Painted Canopy of Mulberry Trees

Leonardo painted sixteen trees, evenly spaced around the room, their trunks emerging from a low rocky outcrop that runs along the base of the walls. Above head height, the branches fan out and interweave across the vault, layering into a canopy dense enough to obscure the architecture beneath it — the ribs and lunettes of the actual vault become, in the painting, simply more branches. Threaded through the foliage is a golden cord that knots and loops around the branches in an intricate, continuous pattern, a motif Leonardo used elsewhere in his decorative and technical drawings and one closely associated with his workshop.

The species is the mulberry — moro in Italian — and the choice is not incidental. It is a pun on Ludovico Sforza’s own epithet, “il Moro,” making the room a piece of dynastic self-presentation as much as a work of art: an artificial grove that turns the duke’s nickname into the room’s entire decorative program. Traces of the ceiling’s original color scheme, along with the coats of arms of the Sforza and Visconti families worked into the design, place the room firmly in the context of Ludovico’s court at its height, shortly before it collapsed.

The Monochrome Fragment and the Wall Drawings

Above the canopy of branches, in the lunettes near the springing of the vault, restorers uncovered a further layer of the decoration: a monochrome section painted in tones of brown and black rather than the greens and golds of the main scheme. This area, sometimes called the “monochrome fragment,” shows root systems and rocky outcrops rendered almost like a technical or geological study, closer to a drawing than a finished painting. It was hidden under later whitewash and overpainting for centuries and only became visible again through twentieth-century conservation work, which is part of why it is less well known to visitors than the mulberry canopy itself.

The monochrome sections are usually read as evidence of Leonardo’s own working method and his interest in the mechanics of plant growth — how roots anchor a tree, how a trunk splits into branches — the same curiosity that shows up in his botanical and geological notebooks. Because this area is more fragile and less complete than the main ceiling, it is often the first part of the room to be roped off or unavailable even when the rest of the Sala delle Asse is open.

Damage, Over-Restoration and a Difficult History

The room’s condition today is the result of centuries of hard use and well-intentioned but damaging intervention, not a single accident. After the Sforza dynasty fell, the castle passed through Spanish, Austrian, and eventually Italian military hands, and the Sala delle Asse was whitewashed and repurposed, at points serving as a stable or storeroom rather than a decorated chamber. The painted surface was covered over and largely forgotten for roughly three centuries.

When the room was rediscovered and restored around the turn of the twentieth century, under the broader restoration of the castle led by Luca Beltrami, conservators repainted extensively rather than simply cleaning and stabilizing the surviving fragments — a common approach at the time but one that art historians now regard as having obscured, and in places replaced, Leonardo’s original work. Later twentieth- and twenty-first-century conservation campaigns have tried to separate genuine surviving pigment from the earlier restorers’ additions, uncovering the monochrome fragment in the process, but the room’s condition means large stretches of what you see are best understood as a heavily restored interpretation of the original rather than an untouched Renaissance surface.

Ongoing Restoration and Why It’s Often Closed

This is the single most important practical fact about the Sala delle Asse, and it is worth being direct about: you should not build a Milan itinerary around seeing this room without confirming, close to your travel date, that it is accessible. Conservation of a fragile, centuries-old painted surface is slow, technical work, and the castle has closed the room for extended restoration campaigns more than once, sometimes for a year or longer at a stretch. Even when restoration isn’t actively underway, the room’s fragility means opening hours can be more limited than the rest of the museums, or access may be granted only to the outer part of the chamber while conservators continue work on the more delicate sections.

None of this is unique to Milan — fragile Renaissance wall and ceiling paintings everywhere require this kind of careful, intermittent management, and it is a sign the room is being taken seriously rather than a reason to distrust it. But it does mean the honest advice is: check the official Castello Sforzesco website or call ahead in the days before your visit, and treat the Sala delle Asse as a possible highlight of your trip rather than a certainty. If access matters enough to you that you’d be disappointed to miss it, build in flexibility, or ask your accommodation to check the day before.

What You Can See When It’s Open

When the Sala delle Asse is accessible, entry is included in the single combined museums ticket that covers all of Sforza Castle’s collections — there is no separate charge for the room itself. Visits are typically brief; this is a single chamber, not a large gallery, and the main experience is standing beneath the vault and looking up into the interlaced canopy, taking in how the trunks at the wall base give way to the woven branches overhead. Because the room is compact and the surface is fragile, expect a controlled, unhurried but time-limited visit rather than a space to linger for a long stretch, and expect signage or a room guide explaining which sections are original, restored, or reconstructed.

Photography rules can vary depending on the current conservation status, and on days when only partial access is granted, you may view the room through a doorway or barrier rather than walk fully inside. None of this diminishes what’s there to see — it simply means the experience is more tightly managed than a typical museum gallery, precisely because of everything the room has already been through.

Significance

The Sala delle Asse matters because it is one of the very few surviving decorative environments that can be attributed to Leonardo da Vinci — most of his other work in Milan either no longer exists (his lost equestrian monument for Francesco Sforza), has suffered its own severe deterioration (the Last Supper), or survives only in drawings and notebooks. A ceiling you can stand beneath, painted for the Sforza court at the height of its confidence, connects the abstract genius of Leonardo’s notebooks to an actual room people once lived and worked in. That the room is damaged, heavily restored, and often closed doesn’t erase that significance — if anything, it’s a reminder of how rare and hard-won access to authentic Renaissance interiors really is, and why Milan’s conservators continue to treat it with such caution.