E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Cannæ.
The place where Han’nibal defeated the Romans under L. Æmil’ius Paulus. Any fatal battle that is the turning point of a great general’s prosperity is called his Cannæ. Thus, we say, “Moscow was the Cannæ of Napoleon Bonaparte.”
