The characterization of early and modern harpsichord wire is described, part of the musical restoration of a 1610 Italian harpsichord. Three sizes of brass wire believed to be original strings of the harpsichord and one type of steel wire also found with the instrument were characterized using a variety of metallographic tests. Three similar sizes of modern brass wire used in the restoration of the instrument were also characterized and compared with the early wire. Microhardness and microstructure were evaluated using optical microscopy, and the overall and surface appearances and chemical constituents of the wires were determined using scanning electron microscopy. Microhardness results were used to obtain estimates of tensile strength of the wires. Various aspects of the results were discussed in relation to three time periods of the instrument: the early 1600s when it was crafted, the late 1800s when it may have been fradulently represented as a mid-1500s instrument, and its current use as a restored instrument.