In the Cast Courts of the Victoria and Albert Museum in London, two enormous plaster columns rise through the full height of the room, split at the midpoint because no single gallery space in Victorian London was tall enough to accommodate the complete original. Red walls, a cast-iron skylight, medieval tomb effigies on the floor below, the Column of Marcus Aurelius visible behind — it is one of the stranger and more magnificent rooms in any museum in the world, and the centerpiece is a reproduction. The V&A made these casts of Trajan’s Column in the 1860s at the request of Pope Pius IX and Queen Victoria, who both wanted to study the reliefs without traveling to Rome. The decision proved more consequential than either of them anticipated. The original column, standing since 113 AD in Trajan’s Forum in Rome, has weathered continuously for nineteen centuries. The Victorian plaster casts now preserve detail that the stone in Rome has since lost. The reproduction is, in some respects, more legible than the original.