According to the ‘Tochar Phadraig’ source (Michigan State University, 2009) — there were three castles built in alignment with one another—namely, MacPhilbins, Castlebourke and Ballybourke castles. The MacPhilbin Castle was built in Aille, in Co. Mayo. They were built in alignment so that they could signal to each other by virtue of lights. All three castles were built by a Norman family called the deBurgos. Not too far from the ruins of the Ballybourke Castle, the Aille river rises once more after flowing underground for three miles (Tochar Phadraig).
Irish Antiquities (N.d.) MacPhilbin’s Castle, Aille. Available at: http://irishantiquities.bravehost.com/mayo/mace/mace.html Accessed 4th of July, 2023.
Michigan State University, Study Abroad Programme. (2009). Ballybourke Castle. Internal Report: Folder 3, Croagh Patrick Heritage Trail—Clogher Environmental Group Ltd. Unpublished.
Tochar Phadraig: A Pilgrim’s Progress, (n.d.) p 23, Stile 41. (Source can be found in above Michigan State University hard copy source folder). No further reference information currently available.