The Sergeant at Law, also known as the Man of Law, is the narrator of the fifth tale of Geoffrey Chaucer's "The Canterbury Tales." The Sergeant at Law is a medieval lawyer and judge described as being thorough in that no errors can be found in his legal writings.
He tells the story of the daughter of the emperor of Rome, a young Christian woman named Constance. She undergoes many tests of her faith during her journeys to Syria and subsequent banishment. She is shipwrecked and lives as a servant among pagans, and she must keep her faith secret at first. She eventually weds King Aella, giving birth to a son who succeeds to the thrones of Northumberland and then Rome.