This strategic fortification controlled access to what was then the main port of Inis Mór, making it a valuable asset for whoever held it. The castle’s documented history stretches back to at least 1574, when records show it as ‘Arkyne’ Castle under the ownership of James Lynch, though it likely existed earlier as a stronghold of the O’Brien clan, who maintained their principal residence on the island at a place called ‘Aircin’.

The castle changed hands several times during its relatively short existence, reflecting the turbulent politics of late medieval and early modern Ireland. After the Lynches, it was granted to John Rawson in 1594, before passing to Teige na Buille O’Flaherty of Arde in 1607. Each transfer of ownership tells a story of shifting allegiances and power struggles between Gaelic Irish families and English colonial authorities, with the castle serving as both prize and pawn in these larger conflicts.

The fortress met its end during the Cromwellian conquest of Ireland in the 1650s, when it was deliberately demolished to make way for a new Cromwellian fort; a common practice as the English Parliamentary forces sought to impose their own military architecture on the Irish landscape. Today, no visible trace of the original castle remains above ground, its stones likely incorporated into the Cromwellian fortification or scattered amongst the island’s countless stone walls. The site serves as a reminder of how successive waves of conquest and colonisation have literally built upon one another, erasing earlier structures whilst leaving their own mark on Ireland’s historical landscape.