A Welsh captain and great pedant, who, amongst other learned quiddities, attempted to draw a parallel between Henry V. and Alexander the Great; but when he had said that one was born at Monmouth and the other at Macedon, both beginning with the same letter, and that there was a river in both cities, he had exhausted his best parallelisms. (Henry V., iv. 7.)
“His parallel is, in all essential circumstances, as incorrect as that which Fluellen drew between Macedon and Monmouth.” —Lord Macaulay.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Fluellen from Fact Monster: