Templetown received its name from the Knights Templar, a brotherhood of monastic warriors originating during the crusades in the Holy Land. When the Anglo-Normans under Strongbow added Ireland amongst their property, military orders soon followed. King Henry II swore to provide 200 Templars after the murder of St. Thomas Beckett, and in 1172 gave away wide stretches of Ireland to fulfill the order, including the southern end of the Hook Peninsula.

The Templars were disbanded in 1307 and their lands were given to their great rivals, the Knights Hospitaller, who built this small place of worship.