David Nolan has the perfect disguise. A white, middle- aged man, dressed in dark slacks and a buttondown shirt — his unvarying uniform — he moves at an unhurried, deliberate pace. His speech is modulated and good-natured, even when discussing the boneheaded decision of some former official or the brutal repression that once defined race relations in historic St. Augustine.

It’s a demeanor more neighborhood hardware salesman than revolutionary, a camouflage that has served him well. Though he’s been at the center of some of the most pitched preservation battles in city history, it’s difficult to find anyone who dislikes Nolan or even heartily disagrees with him. Whether it’s his calm delivery, his residual New England accent or the chuckle that often seems to follow his fiercest indictments, Nolan is as reasonable a radical as one is likely to meet.

Still, he’s a radical. Largely self-taught (he never finished college) he’s become the city’s unofficial historian through sheer force of will. His pet issues — preservation and Civil Rights history — are often in conflict with St. Augustine’s official line. He disparages the city’s penchant for marketing faux Colonial history, for preferring themepark appeal to sometimes uncomfortable realities. He’s butted heads with all manner of city officials and business types, fighting their demolition plans and calling attention to their foolishness. And he’s effected a real change in the way both black and white residents speak and think about city history. It’s largely because of Nolan, for example, that the covered portion of the Plaza de la Constitucion is now universally recognized as a former Slave Market. In the late ’80s, he learned that human chattel was bought and sold there, a fact the city was reluctant to acknowledge. (A historic marker located there calls it the “birthplace of weights and measures,” but makes no mention of slaves.) Nolan, however, dusted off the fact and refused to let die. It is now widely known and accepted as true.

“When I came here [in 1977], the concept of history in St. Augustine was that people dressed up in funny costumes on St. George Street in fake buildings, where they sold T-shirts and rubber alligators,” he jokes. There are still funny costumes and rubber alligators, but today they’re tempered by Nolan’s unforgiving eye and unimpeachable memory. He’s succeeded in holding the city and its residents accountable to history — and making sure they don’t forget it.