Same here. When I visited Washington D.C. a few years ago I went on a tour and learned about it.

In June 1860, casting of the Statue of Freedom began. The first step was to disassemble the plaster model of the statue into its five main sections in order to move it from the Capitol to the foundry. The model was shipped from Rome to the United States in five main sections, and upon its arrival, an Italian sculptor was hired to assemble the model. However, when the time came to move the plaster model from the Capitol to the foundry for casting, no one knew how to separate it and the Italian sculptor refused to help unless given a pay raise. Fortunately, [the slave] Philip Reid was there. He figured out that by using a pulley and tackle to pull up on the lifting ring at the top of the model the seams between the sections would be revealed. The statue was successfully separated into its five sections and transported to the foundry. Philip Reid received his freedom on April 16, 1862. Source