Leonine verse is a type of versification based on an internal rhyme between a word within the line before a caesura and a word at the end, and commonly used in Latin verse of the European Middle Ages. The proliferation of such conscious rhymes, uncommon in Classical Latin poetry, is traditionally attributed to a probably apocryphal monk Leonius, who is supposed to be the author of a history of the Old Testament (Historia Sacra) preserved in the Bibliothèque Nationale of Paris. It is possible that this Leonius is the same person as Leoninus, a Benedictine musician of the twelfth century, in which case he would not have been the original proliferator of the form.
In English Leonine verse is sometimes referred to disparagingly as "jangling verse", for example by 19th-century antiquaries and classical purists, who considered it absurd, coarse, and a corruption of and offensive to the high ideals of classical literature. William Shakespeare used it in a drunken song sung by Caliban in The Tempest.