According to accounts which vary in some of the details, in 340 BCE the Byzantines and their allies the Athenians were under siege by the troops of Philip of Macedon. On a particularly dark and wet night Philip attempted a surprise attack but was thwarted by the appearance of a bright light in the sky. This light is occasionally described by subsequent interpreters as a meteor, sometimes as the moon, and some accounts also mention the barking of dogs. However, the original accounts mention only a light in the sky, without specifying the moon. To commemorate the event the Byzantines erected a statue of Hecate lampadephoros (light-bearer or bringer). This story survived in the works of Hesychius of Miletus, who in all probability lived in the time of Justinian I. His works survive only in fragments preserved in Photius and the tenth century lexicographer Suidas. The tale is also related by Stephanus of Byzantium, and Eustathius.
"In 340 BCE, however, the Byzantines, with the aid of the Athenians, withstood a siege successfully, an occurrence the more remarkable as they were attacked by the greatest general of the age, Philip of Macedon. In the course of this beleaguerment, it is related, on a certain wet and moonless night the enemy attempted a surprise, but were foiled by reason of a bright light which, appearing suddenly in the heavens, startled all the dogs in the town and thus roused the garrison to a sense of their danger. To commemorate this timely phenomenon, which was attributed to Hecate, they erected a public statue to that goddess [...]" William Gordon Holmes, The Age of Justinian and Theodora, 2003 p5-6;http://www.basicpatterns.com/byzantium/encyclopedia.htm
"If any goddess had a connection with the walls in Constantinople, it was Hecate. Hecate had a cult in Byzantium from the time of its founding. Like Byzas in one legend, she had her origins in Thrace. Since Hecate was the guardian of "liminal places," in Byzantium small temples in her honor were placed close to the gates of the city. Hecate's importance to Byzantium was above all as deity of protection. When Philip of Macedon was about to attack the city, according to he legend she alerted the townspeople with her ever-present torches, and with her pack of dogs, which served as her constant companions. Her mythic qualities thenceforth forever entered the fabric of Byzantine history. A statue known as the 'Lampadephoros' was erected on the hill above the Bosphorous to commemorate Hecate's defensive aid." Vasiliki Limberis, Divine Heiress, Routledge, 1994, p126-127
Note: color change mine to indicate the known references to this story. It should also be noted that much of the cited material appears to be reproduced from Wikipedia entries. Actual translations of the source material I have been unable to discover so have not been able to include references or linkages.
Her location near to the Bosporus places her still within the juncture of ancient Anatolia (modern Turkey) and ancient Thrace (modern Bulgaria / Greece and Turkey). It also keeps within the tradtional notion that Hekate / Hecate originated in one or the other.
The statue is believed to have been erected on the hideside overlooking the Bosphorus Straights near modern day Instanbul. To my knowledge though no known location has been identifed as to where it may have been placed. Additionally I have been unable to discover any specific information pertaining to the specifics of the statue in regard to size, construction material or even what it looked like.
It should also be pointed out that while most translations and referenced accounts point to Hekate / Hecate as the source of the revealing light some accounts indicate it was Artemis (Or Diana in some). It is possible part of the issues arises from the syncretism of Artemis and Hekate / Hecate lore in later periods. Yet it is known that there were sanctuaries to both Hekate / Hecate and Artemis in Byzantium.
On a historical note the city known as Byzantium was later known as Constantinople then changed to its modern name of Istanbul.
Of interest is the association of the Cresent Moon and star being equated to Hecate / Hekate and to the city of Byzantium
Though associated with the Sassanid Persians and with Mithradates VI Eupator (who for a time incorporated the city into his empire), by the late Hellenistic or early Roman period, the star and crescent motif had been associated to some degree with Byzantium. For example, some Byzantine coins of the 1st century BCE and later show the head of Artemis with bow and quiver, and feature a crescent with what appears to be a six-rayed star on the reverse.
Devotion to Hecate was especially favored by the Byzantines for her aid in having protected them from the incursions of Philip of Macedon. Her symbols were the crescent and star, and the walls of her city were her provenance.http://www.basicpatterns.com/byzantium/encyclopedia.htm
By the late Hellenistic or early Roman period, the star and crescent motif had been associated to some degree with Byzantium . If any goddess had a connection with the walls in Constantinople , it was Hecate . Hecate had a cult in Byzantium from the time of its founding.http://www.enotes.com/topic/Star_and_crescent
The attachment shows a coin with the depiction of Artemis upon one side and the Cresent Moon and radiating star on the other. It does need to be noted that I have not found any coins depicting Hekate / Hecate on recognized coins from Byzantium. (not working at the moment so will have to figure out how to attach it)
For me this story sort of evolved from the attached coin I had purchased. It revealed an area of associatioin to both Artemis and Hekate / Hecate which I had been unaware of. Research wise it has proven difficult to trace for the references in both the Numismatics facet and the historical / mythological facet utilize the same referenced material often repeated without direct sourcing information.
But one thing I have discovered is that the Cresent Moon and radiating star seems to have originated as a symbol for Hecate / Hekate from her association and protection of Byzantium. A symbol that even today flies over the city of Byzantium now know as Istanbul.