Portora Castle was built for Sir William Cole who purchased the land in 1612. It is strategically positioned by the narrow exit of the River Erne into the Lower Lough Erne.
Sir Michael Cole and his family moved to Portora Castle in 1710 when their previous residence, Enniskillen Castle, was hit by fire. They remained there until about 1716, when Sir Michael's son, John Cole (1680–1726), started building Florence Court.
Three of the flankers remain, the two on the west, flanking the walls of the castle. These round towers, about 3m in diameter, have several gun loops. Inside the castle can be seen proper fireplace chimneys in the north and west walls.
The ford at Portora was important in the Erne Waterways and must have seen considerable traffic in peace and war. In the course of the Erne Drainage Scheme (1951–1960) a bronze dirk and stone axes were recovered at this point. The castle is now in ruins, partly because a group of truanting school-boys from nearby Portora Royal School, now Enniskillen Royal Grammar School, experimenting with gunpowder they learnt how to create in chemistry class, blew up a section in the latter part of the 19th century. They also tried digging under the building which added to its dereliction.
References:The Gravensteen is a castle in Ghent originating from the Middle Ages. The name means 'castle of the counts' in Dutch. Arnulf I (918–965), Count of Flanders, was the first to fortify this place, building a medieval bastion on this high sand dune, naturally protected by the river Leie and its marshy banks. This bastion consisted of a central wooden building and several surrounding buildings, also in wood.
In the early 11th century, the wooden building was replaced by a stone residence, consisting of three large halls that made up three storeys, connected by a stone stairwell. The monumental stone staircase, the light openings, the fireplaces built into the walls and the latrines were signs of considerable luxury and comfort in those days. There was probably also a tower.