Daniel Liebskind’s startling addition to the Military History Museum in Dresden, Germany presents us with what appears to be a historic classical building brutally penetrated by a stiletto-like glass shard. Thrilling to fans of “transgressive” contemporary architecture and horrifying to defenders of historic places, the project—by no means unique in its apparently contemptuous treatment of a handsome older building—is at the center of current debate about how new architecture should relate to historic structures and contexts.

While Liebskind’s projects in Dresden and elsewhere may be extreme cases, current tendencies in design worldwide have tended to dramatize contrast with historic neighbors in the design of additions and infill buildings. People are often shocked to learn that in some cases preservation authorities not only have not prevented the resulting visually dissonant interventions, but have actively encouraged them. The New York City Landmarks Preservation Commission has approved a number of counter-contextual projects, such as Jeanne Gang’s addition to the Natural History Museum, raising the question of what, in the end, preservationists are preserving if they allow historic places to be radically altered by additions.

Professionals in the leadership of preservation in the United States and Europe often justify such decisions by reference to two doctrinal documents—in the US, the Secretary of the Interior’s Standards for Rehabilitation of 1977 and, internationally, the ICOMOS Venice Charter of 1964—but few have closely examined what these texts actually say.

The National Park Service published the standards as eligibility criteria for preservation projects receiving federal matching grants or tax credits. Though never intended as a universal preservation policy, many local review boards nationwide apply them in contexts never contemplated by their authors. Problems arise in interpreting the language of Standard Nine: “New additions, exterior alterations, or related new construction shall not destroy historic materials that characterize the property. The new work shall be differentiated from the old and shall be compatible with the massing, size, scale, and architectural features to protect the historic integrity of the property and its environment.”

The need for a distinction between historic and new work is one of the core values of conservation theory dating back to the nineteenth century, when modern completions of damaged ancient monuments in Rome used subtly different materials to make this distinction while also presenting the monument as a whole. This interpretation seeks to balance visual continuity with an avoidance of confusion between original and restored features but, given the tendency of modern designers to celebrate what separates contemporary and historic work, they have often sought a more conspicuous distinction. Stylistic and material contrast presents an uncomplicated and unambiguous way to differentiate, though at the risk of visual dissonance. What began as a need to avoid deceiving later restorers who might mistake a previous addition or restoration for original material, ended up as a difference that precludes any sense of harmony or wholeness.

Standard Nine’s call for compatibility with respect to massing and size suggested another simplification: The new construction is acceptable if about the same size as the historic structure, or at least no larger. Reducing compatibility to size made it quantifiable, thus making judgment seem less subjective, even if doing so disregarded the remaining issues of scale and “architectural features.”

This interpretation of Standard Nine was for many years reinforced by the Guidelines published by the Park Service illustrating banal additions that were in almost every case visual blots on their host buildings (though unmistakably not historic and not too big). Only in 2010 did the Park Service issue a revised edition of its Preservation Brief 14: New Exterior Additions to Historic Buildings: Preservation Concerns, for the first time illustrating additions that satisfy Standard Nine but are stylistically harmonious with the historic structures they join. In recent years, a more subtle balance between distinction and continuity has remained elusive, and the Park Service’s revision of the Guidelines just last year did little to clarify the matter. To be sure, Liebskind’s signature violations of historic buildings would never be accepted under Standard Nine, but other, less egregious cases have been approved, especially by local authorities, when “differentiation” is prioritized over “compatibility.”

In Europe, the reigning document is the 1964 ICOMOS Charter of Venice. In what is mostly unexceptionable guidance about monument conservation, the key passage, under the heading “Restoration,” appears in Article 9: “…restoration…must stop at the point where conjecture begins, and in this case moreover any extra work which is indispensable must be distinct from the architectural composition and must bear a contemporary stamp.”

Many interpret this language, too, to require a contrasting modernist style for new elements and to prohibit new work using traditional styles. Supporters often point to Carlo Scarpa’s contemporaneous renovation of the Castelvecchio of Verona,,in which the new and historic elements are sharply juxtaposed, as an exemplary illustration of Article 9. But this interpretation violates other articles in the same charter, such as Article 6, which says, “No new construction… which would alter the relations of mass and colour must be allowed.” Despite this contradiction, the language of Article 9 has been applied far beyond the originally intended scope. Scarpa’s work, like it or not, is not a restoration at all, but a highly creative remodeling that also entailed extensive demolition of post-medieval layers. Since the point of preservation is to safeguard historical significance, the Castececchio is an inappropriate model for ordinary preservation projects.

Recent research suggests the apparent contradiction in the Venice Charter is due to a translation error.  A more accurate English translation of the original French text of Article 9 would be “any extra work that is indispensable is a matter of architectural design and therefore will bear the imprint of our time.” There is no requirement for a contrasting style but simply a call for a distinction between restoration proper and new design, which, in any case, must not alter the visual character of the setting.

In 2005, the Vienna Memorandum declared that “…urban planning, contemporary architecture and preservation of the historic urban landscape should avoid all forms of pseudo-historical design, as they constitute a denial of both the historical and the contemporary alike.” In this case, the “differentiators” tried proscribing any new work in the same style as the historical building because it would undermine the conventional understanding of art history as an irreversible succession of distinctive styles and periods. To maintain that fiction, the historical timeline must remain “legible.”

The memorandum thus shifts the emphasis from preserving the character of the place to prioritizing how buildings express their time. This attitude underlies the view of those preservationists who see any new traditional design as “false history” or “pastiche.” This widespread prejudice arises from a misconception of history and encourages the kind of alien forms that Liebskind uses in his assault on the Military History Museum. But this view is contrary to the aims of historic preservation, which should involve safeguarding heritage sites and their contexts, not determining what style of architecture ought to represent “our time.”  

Recognizing the need for clarity, the ICOMOS General Assembly’s Valletta Principles of 2011 return the focus of conservation to preserving the character of historic places and explicitly reject stylistic or material contrast as a required strategy for new construction: “Regardless of style and expression, all new architecture should avoid the negative effects of drastic or excessive contrasts and of fragmentation and interruptions in the continuity of the urban fabric and space. Priority must be given to a continuity of composition that does not adversely affect the existing architecture but at the same time allows a discerning creativity that embraces the spirit of the place.”

Even though the Valletta Principles carry the same authority as the Venice Charter of a half-century before, many in the preservation field remain stuck on the conventional misinterpretation of the earlier document. This is why we must look at the entire series of Charters and declarations where, despite some dissenting examples, we can trace an emerging consensus: Historic preservation should neither require nor prohibit any style of new construction, but should support continuities of character, scale, materials, and craft that can bring harmony to the dialogue between old and new.

Official guidance in the field, interpreted correctly, offers valuable perspective on issues of new building in old places. For this reason, students in the graduate program in historic preservation at the Notre Dame School of Architecture closely read the international documents on conservation during their semester in Rome, and are currently preparing a study guide to make this information more available to professionals and students everywhere. This should open up new directions for architectural design in heritage settings, too long locked into a contrived and ultimately destructive opposition.

Featured image: Daniel Libeskind’s contemporary addition to the Military History Museum, in Dresden, Germany. Photo via Studio Libeskind.