Columnae Herculis

Calque of Ancient Greek Ἠράκλειοι Στῆλαι (Ērákleioi Stêlai).

Columnae Herculis f pl (genitive Columnārum Herculis); first declension

1. Pillars of Hercules (two promontories at the Strait of Gibraltar)
   • c. 43 CE, Pomponius Mela, A Description of the World 2.95.1:

     fit deinde angustissimum pelagus, et proxima inter sē Eurōpae atque Āfricae lītora montēs efficiunt, ut initiō dīximus Columnae Herculis, Abila et Calpēs, uterque quidem sed Calpēs magis et paene tōtus in mare prōminēns.

     Then the strait becomes very narrow, and the nearest shores of Europe and Africa form mountains, as we said in the beginning, the Pillars of Hercules, Abila and Calpes, both of them, but Calpes more and almost entirely protruding into the sea.

   • c. 77 CE – 79 CE, Pliny the Elder, Naturalis Historia 6.212.2:

     continentur Gedrōsī, Carmānī, Persae, Elymaeī, Parthyēne, Arīā, Sūsiānē, Mesopotamiā, Seleucīā cognōminātā Babylōniā, Arabiā ad Petrās usque, Syriā Coelē, Pēlūsium, Aegyptī īnferiōra, quae Chōra vocātur, Alexandrīā, Āfricae maratimā, Cȳrēnaicā oppida omnia, Thapsus, Hadrūmētum, Clupeā, Carthāgō, Uticā, uterque Hippō, Numidiā, Mauretāniā utrāque, Atlanticum mare, columnae Herculis.

     They are contained by the Gedrosi, Carmanians, Persians, Elymaeans, Parthia, Aria, Susa, Mesopotamia, Seleucia, also known as Babylonia, Arabia as far as Petra, Coele-Syria, Pelusium, Lower Egypt, which is called Chora, Alexandria, maritime Africa, all the towns of Cyrenaica, Thapsus, Hadrumetum, Clupea, Carthage, Utica, both Hippos, Numidia, both Mauritanias, the Atlantic Ocean, and the Pillars of Hercules.

First-declension noun with an indeclinable portion, plural only.