2 Groats 'Dobbelen Penninck Jans' - John IV

John IV became Duke of Brabant at seventeen, and his coinage reflects the financial disorder of a minority government scrambling for revenue. The billon standard on this issue was actively debased mid-series — the alloy specification climbed from roughly 40 to 52 percent silver across the production run, an unusual upward revision likely driven by pressure from Brabant's merchant estates, who had been protesting coin quality since at least 1415. Finding an example struck from the later, richer alloy requires knowing the die diagnostics; Witte documents the type but the internal chronology of the adjustment remains imprecisely mapped.