What is "equitan"

"Equitan" is a Breton lai, a type of narrative poem, written by Marie de France sometime in the 12th century. The poem belongs to what is collectively known as The Lais of Marie de France. Like the other lais in the collection, Equitan is written in the Anglo-Norman language, a dialect of Old French, in rhyming octosyllabic couplets. In this 320 line poem, the author cautions that those who plot to harm another person may find only their own misfortune.