This tragedy is founded on historical truth. A duke of Brittany, in the year 1387, commanded the lord of Bavalan to assassinate the constable of Clisson: Bavalan, the day after, told the duke it was done: the duke becoming sensible of the horror of his crime, and apprehensive of the fatal consequences of it, abandoned himself to the most violent despair: Bavalan, after giving him time to repent, at length told him that he had loved him well enough to disobey his orders.