These were indeed battles on the mainland of Europe in whuch the exiled Irish troops called "The Wild Geese" fought as mercenaries. Lord Clare was the leader of a Regiment known after him as "Clare's Dragoons". Their gratest triumph, among many, was the Battle of Ramilles. When the English forces had turned the French, Lord Clare spurred his Irish troops into action with the battle cry "Cuimhnígí ar Luimneach" (Remember Limerick!). The English were routed.
The words here given don't appear to be traditional in origin. They sound very like the sort of thing nineteenth century Irish romantic writers penned.
For further details, consult a historian.
Annraoi