Every death is the shutting of a book, but when William H. Pierson, the prominent historian of architecture, died last December, it seemed more like the close of a geological era. He was the last survivor of that trio of extraordinary—and extraordinarily long-lived—Williams College professors who for a half century were major forces in the world of American art. All lived to be nonagenarians and remained professionally active to the end, not only Pierson (1911–2008) but Lane Faison (1907–2006) and Whitney Stoddard (1913–2003) as well. Through a travesty of language they were dubbed the “Holy Trinity,” to their great chagrin, while their former students became known as the “Williams Art Mafia.” The metaphors are grotesquely mixed: It hardly seems decent that a Puritan establishment like Williams should be trafficking in trinities and mafias. (To be sure, the more historically defensible “Williams Art Conventicle” does not pass trippingly over the tongue.)

Yet to describe the intensity of devotion and veneration inspired by those three professors seems to demand sacral language, even the blood loyalty of omertà. Collectively, they produced the most significant cohort of museum directors ever to come from one American institution of higher learning. Their students went on to run the Getty Trust and the Chicago Art Institute (James N. Wood), the National Gallery of Art (Earl A. Powell III), the Guggenheim (Tom Krens), and the Museum of Modern Art (Glenn Lowry). One must also count Kirk Varnedoe, who left his position as senior