18Buttermilk CastleButtermilk Castle built on a ledge of rock below Ballyhack was originally a steep rock known as "Dun alof" supposed to have been built by a Dane named Olaf, who took advantage of ite excellent position for trading purposes. On the arrival of the Normans, so at Bag and Bun and others at Waterford Hervey De Montmarisco at St. Mary's Abbey (opposite Castle) in order to hold place for convenience of coming expedition.
The three thousand natives under O'Phelan of Waterford, attacked Normans who were strongly entrenched in ruins of the old castle. They were totally unprepared for deadly range of Flemish cross-bows, every arrow brought down a man.
Confusion ensued - Normans sallied forth and Irish fled to boats, leaving 500 soldiers and seventy five of the chief citizens of Waterford as prisoners. These were unhumanly massacred by Hervey - their legs were first broken, and then they were hurled into the tide. The waters runs swift and deep close to the rock and would quickly engulf the numbers of victims.