Ferrex and Porrex
Two sons of Gorboduc, a mythical British king. Porrex drove his brother from Britain, and when Ferrex returned with an army he was slain, but Porrex was shortly after put to death by his mother. One of the first, if not the very first, historical play in the English language was Ferrex and Porrex, by Thomas Norton and Thomas Sackville.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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