[2] During the Hundred Years' War, grants of £10 were issued to landowners in the Pale to construct fortified houses to aid in their defence in the army's absence.
[3] It was extended in the 16th century by Dame Jenet Sarsfield, widow of Robert Plunkett, 5th Baron of Dunsany and of Sir John Plunket of Dunsoghly Castle, Dublin, who added a new entrance and other extensions.
Henry Osborne (d.10 May 1828)[4] also owned Cooperhill Brickworks which supplied red bricks to many of Drogheda's buildings, including Saint Joseph's Convent (1896), Dublin Road.
[5] He also bought the horse pulling a stagecoach in 1827 which later gave birth to Abd-El-Kader, the first successive Grand Nationals winner (for his trainer son Joseph) in 1850 and 1851.
[6] Today the upper floors of the tower have been made available to rent and the castle is open to the public two days a week for most of the year.