JUSTINUS, JUSTYN is Januarie's brother in The Merchant's Tale. His name indicates his character, for Justinus is a just man and warns Januarie against marriage to a very young woman. He is the opposite of his brother Placebo, who seeks to please Januarie and agrees with his plan to marry May. Justinus attempts to show Januarie that his fantasies about marriage are ephemeral by quoting from the philosophers, but Januarie says that Seneca is not worth a straw. [Damyan: Januarie: May: Placebo]

The name occurs only in medial positions. Justinus, the Latin form, appears in MerchT 1477, 1519, 1655; Justyn, the English contraction, in MerchT 1689.