Strabo, Geography
H.C. Hamilton, Esq., W. Falconer, M.A., Ed.

It is probable that the places themselves took the same name [as the monuments], especially after time had destroyed the boundary marks which had been placed there. For instance, at the present day the altars of the Philæni no longer exist, but the place itself bears that designation. Similarly they say that in India neither the pillars of Hercules or Bacchus are to be seen, nevertheless certain localities being described and pointed out to the Macedonians, they believed that those places were the pillars in which they discovered any trace either of the adventures of Bacchus or Hercules. In the instance before us, it is not improbable that they who first [visited these regions], set up boundary marks fashioned by the hand of man, such as altars, towers, and pillars, in the most remarkable situations, to indicate the farthest distance they had reached, (and straits, the surrounding mountains, and little islands, are indubitably the most remarkable situations for pointing out the termination or commencement of places,) and that after these human monuments had decayed, their names descended to the places [where they had stood]; whether that were the little islands or the capes forming the strait. This latter point it would not be easy now to determine; the name would suit either place, as they both bear some resemblance to pillars; I say bear some resemblance, because they are placed in such situations as might well indicate boundaries. Now this strait is styled a mouth, as well as many others, but the mouth is at the beginning to those sailing into the strait, and to those who are quitting it at the end. The little islands at the mouth having a contour easy to describe, and being remarkable, one might not improperly compare to pillars. In like manner the mountains overlooking the strait are promi- nent, resembling columns or pillars. So too Pindar might very justly have said, ‘The Gaditanian Gates,’ if he had in mind the pillars at the mouth; for these mouths are very similar to gates. On the other hand, Gades is not in a position to indicate an extremity, but is situated about the middle of a long coast forming a kind of gulf. The supposition that the pillars of the temple of Hercules in Gades are intended, appears to me still less probable. It seems most likely that the name was originally conferred not by merchants, but generals, its celebrity afterwards became universal, as was the case with the Indian pillars. Besides, the inscription recorded refutes this idea, since it contains no religious dedication, but a mere list of expenses; whereas the pillars of Hercules should have been a record of the hero's wonderful deeds, not of Phoenician expenditure.