Enniskillen Castle was originally built by Hugh ‘the Hospitable’ Maguire around 1428 and fell to the Irish in 1595, after being besieged by Captain John Dowdall’s troops in 1594 and falling after a short siege on 2 February, when its occupants were massacred after they surrendered. The fortress finally fell to the Irish in 1595.
Guarding one of the few passes into Ulster, Enniskillen Castle has been strategically important throughout its history. The earliest known reference to Enniskillen Castle occurs in the Annals of Ulster in 1439. A text refers to King Tomas Og Maguire being held prisoner at his own castle in Enniskillen.
Captain William Cole remodeled and refurbished the castle adding the watergate in 1609 and again to respond to a French invasion threat in 1796.