The lands here were controlled by a branch of the FitzGeralds of Kiltranyn, also known as Burnchurch, who traced their lineage back to Maurice FitzGerald after 1324. This cadet branch of the family became known as the Barrons, and by 1425, Hugh Barrye’s heir held Killesk for a quarter of a knight’s fee, a feudal measurement that indicated military service owed to a lord.

The Barron family maintained their grip on Killesk for centuries. When William Barron died in 1568, he owned both the land and castle at Killesk. Nearly a century later, the Civil Survey of 1654;6 recorded another William Barron holding 300 acres across Killesk, Knockagh and Drilstown, along with what was described as a small castle at Killesk. This castle appears as a separate structure from the church on both the 1839 and 1940 Ordnance Survey maps, positioned at the southern end of a low spur running north to south.

The distinction between church and castle at this site has long puzzled historians and locals alike. When antiquarian John O’Donovan visited around 1840, local residents could still point out the separate locations of both structures. However, the confusion likely stems from the fortified church itself, which may have been converted to secular use by the 16th century and occupied as a residence by the Barrons. This transformation from sacred to secular space was not uncommon in post;Reformation Ireland, where many religious buildings found new life as defensive strongholds or family homes.