E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Pillars of Hercules (The).
The opposite rocks at the entrance of the Mediterranean Sea, one in Spain and the other on the African continent. The tale is that they were bound together till Hercules tore them asunder in order to get to Gads (Cadiz). The ancients called them Calp and Abyla; we call them Gibraltar Rock and Mount Hacho, on which stands the fortress of Ceuta (Kutah).