On this date in 1676, an indigenous Nipmuc named Matoonas was marched into Boston, condemned by a summary judicial proceeding, and immediately shot on Boston Common. Though he was a so-called “Jesus Indian” — a converted Christian — Matoonas had become a principal adversary of the European colonists once long-building tensions exploded into King Philip’s War. To the communal grievances that made up this war, Matoonas brought a very personal injury: back in 1671, his son Nehemiah had been accused by English colonists of murder and executed on that basis. And not just executed, but his rotting head set up...