A study of the limerick form, its history, and notable examples
The following attempts to use historical evidence to uncover the origins, and development of the limerick throughout history. If you would like a breif example of what a limerick is you can view some I have wrote here. Regarding the history of limericks it appears to be a highly debated topic. If you are not interested in a more thorough analysis of a limerick you can view my On Limerick Composition, for a practical guide to the composition of limericks.
It would seem that some "Proto-Limericks" can be indentified within early medieval European verse. Specifically the identification of a 11-century French manuscript of which contained a five-line poem with similar rhythmic patterns, though its rhyme scheme differed from the modern AABBA structure. Similar examples can be drawn from Latin prayers such as a hymn attributed to Thomas Aquinas (1225-1274), which scholars cite as an early limerick-like composition despite its clear lack of humurous intent.