An imaginary king of Africa, of great wealth, who “disdained all womankind.” One day he saw a beggar-girl from his window, and fell in love with her. He asked her name; it was Penelophon, called by Shakespeare Xenelophon (Love's Labour's Lost, iv. 1).
They lived together long and happily, and at death were universally lamented. (Percy's Reliques, book ii. 6.)
“King Cophetua loved the beggar-maid.”
Shakespeare: Romeo and Juliet. ii. 1.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894