On Friday, July 10, 1840, William Maxwell walked into H. J. Morrison’s store at the southeast corner of Main and Second Streets in Platteville, Wisconsin Territory, and purchased a pair of pants and a bar of soap. Maxwell, a Black man, worked as a lead miner at one of Platteville’s mining ranges. He was one of thousands of lead miners working in the upper Mississippi River valley’s lead region, which encompasses modern-day southwest Wisconsin, northwest Illinois, and northeast Iowa. Maxwell’s origins are unknown, but he must have had a connection with John H. Rountree, an influential white Platteville businessman, for Maxwell was living with the Rountree family that summer. In his spare time, Maxwell prospected for lead on Rountree’s property west of town. If he discovered a vein of lead…