Ogham is an early medieval script in which letters are represented by groups of notches and strokes cut along the edge of a stone, most often recording a personal name in a formulaic inscription. These four stones were not always roadside curiosities; they were removed from a burial site several kilometres away and repurposed as a kind of informal avenue, their original arrangement broken up and their ceremonial context long since dissolved.

The stones came from Ballinrannig townland, at a site known as Cillvickillane, or Cill Mhic Uíleáin. A storm at the end of the 18th century stripped back the ground there and exposed an extraordinary concentration of material: seven ogham stones, a possible fragment of an eighth, a cross-inscribed stone, a number of graves, quantities of bone, and the ruins of several houses. A sketch made by the antiquarian Windele in 1838 shows the stones arranged in a rough semi-circle on top of a mound, with a slab-lined grave positioned nearby. The picture is of a small early Christian burial enclosure, undisturbed for centuries until the weather intervened. In the mid-19th century, Lord Ventry removed six of the seven ogham stones from the site. Four, including the one at Coláiste Íde inscribed BROINIONAS, were relocated to the driveway of Burnham House, the building that later became the college. Two others went to the grounds of Chute Hall near Tralee. Only the seventh stone was left at Ballinrannig.

The stone carrying the inscription BROINIONAS stands 1.82 metres high and is relatively slender, measuring roughly 26 centimetres wide and 25 centimetres thick. Its top is broken, though scholars consider the inscription itself to be complete. As ogham inscriptions go, it is a single personal name, modest in scope but intact across more than a millennium, now marking a driveway rather than a grave.