The Pillars of Hercules (, ) was the phrase that was applied in Antiquity to the promontories that flank the entrance to the Strait of Gibraltar. The northern Pillar is the Rock of Gibraltar in the British overseas territory of Gibraltar. A corresponding North African peak not being predominant, the identity of the southern Pillar has been disputed through history, with the two most likely candidates being Monte Hacho in Ceuta and Jebel Musa in Morocco.

Naming

According to Greek mythology adopted by the Etruscans and Romans, when Hercules had to perform twelve labours, one of them was to fetch the Cattle of Geryon of the far West and bring them to Eurystheus, and this marked the westward extent of his travels. A lost passage of Pindar quoted by Strabo was the earliest reference in this context: "the pillars which Pindar calls the 'gates of Gades' when he asserts that they are the farthermost limits reached by Heracles." According to Plato's account, the lost realm of Atlantis was situated beyond the Pillars of Hercules, in effect placing it in the realm of the Unknown.

According to some Roman sources, while on his way to the island of Erytheia Hercules had to cross the mountain that was once Atlas. Instead of climbing the great mountain, Hercules used his superhuman strength to smash through it. By doing so, he connected the Atlantic Ocean to the Mediterranean Sea and formed the Strait of Gibraltar. One part of the split mountain is Gibraltar and the other is either Monte Hacho or Jebel Musa. These two mountains taken together have since then been known as the Pillars of Hercules, though other natural features have been associated with the name. Diodorus Siculus, however, held that instead of smashing through an isthmus to create the Straits of Gibraltar, Hercules instead narrowed an already existing strait to keep monsters in the Atlantic Ocean from entering the Mediterranean Sea.

Pillars as portals

Image:Columnas Plus Ultra.png|Device of Charles V in Seville's city hall.
Image:Escudo de España ajunstado a la norma heráldica.svg|Spanish coat of arms depicting the columns.

The Pillars appear as supporters of the coat of arms of Spain, originating from the famous impresa of the Holy Roman Emperor, Charles V, King of Spain. The motto Plus Ultra (Latin for further beyond) indicates the desire to see the Pillars as an entrance to the rest of the world rather than as a gate to the Mediterranean Sea. It also indicates the overseas possessions that Spain had.

Phoenician connection

Beyond Gades, several important Mauritanian colonies (in modern-day Morocco) were founded by the Phoenicians as the Phoenician merchant navy pushed through the Pillars of Hercules and began constructing a series of bases along the Atlantic coast starting with Lixus in the north, then Chellah and finally Mogador.

Near the eastern shore of the island of Gades/Gadeira (modern Cádiz, just beyond the strait) Strabo describes the westernmost temple of Tyrian Heracles, the god with whom Greeks associated the Phoenician and Punic Melqart, by interpretatio graeca. Strabo notes that the two bronze pillars within the temple, each eight cubits high, were widely proclaimed to be the true Pillars of Hercules by many who had visited the place and had sacrificed to Heracles there. But Strabo believes the account to be fraudulent, in part noting that the inscriptions on those pillars mentioned nothing about Heracles, speaking only of the expenses incurred by the Phoenicians in their making. The columns of the Melqart temple at Tyre were also of religious significance.

Dante's Inferno

In Inferno XXVI Dante Alighieri mentions Ulysses in the pit of the Fraudulent Counsellors and his voyage past the Pillars of Hercules. Ulysses justifies endangering his sailors by the fact that his goal is to gain knowledge of the unknown. After five months of navigation in the ocean, Ulysses sights the mountain of Purgatory but encounters a whirlwind from it that sinks his ship and all on it for their daring to approach Purgatory while alive, by their strength and wits alone.

Sir Francis Bacon's Novum Organum

The Pillars appear prominently on the engraved title page of Sir Francis Bacon's Instauratio Magna ("Great Renewal"), 1620, the foreword to his Novum Organum. The motto along the base offers the optimistic promise Multi pertransibunt et augebitur scientia ("Many will pass through and knowledge will be the greater").

Alternate locations

According to a controversial theory by Italian journalist Sergio Frau, the Pillars of Hercules in fact referred to the area of water between "Greater Sicily" (including Malta, Sicily, and the surrounding islands joined by a land bridge) and Tunisia. However, Frau's theory has been dismissed by a group of 250 academics