The art of war, if art it could in their case be called, was in a much less forward stage among the Irish in the twelfth and thirteenth centuries than amongst the Normans. Of the science of fortification they perhaps knew no more than they had learned in their long struggle with the Danes and Norwegians. To render roads impassable, to strengthen their islands by stockades, to hold the naturally difficult passes which connect one province or one district with another—these seem to have been their chief ideas of the aid that valour may derive from artificial appliances. The fortresses of which we hear so frequently, during and after the Danish period, and which are erroneously called _Danes'-forts_, were more numerous than formidable to such enemies as the Normans. Some of these earth-and-stone-works are older than the Milesian invasion, and of Cyclopean style and strength. Those of the Milesians are generally of larger size, contain much more earth, and the internal chambers are of less massive masonry. They are almost invariably of circular form, and the largest remaining specimens are the Giant's Ring, near Belfast; the fort at Netterville, which measures 300 paces in circumference round the top of the embankment; the Black Rath, on the Boyne, which measures 321 paces round the outer wall of circumvallation; and the King's Rath, at Tara, upwards of 280 in length. The height of the outer embankment in forts of this size varied from fifteen to twenty feet; this embankment was usually surrounded by a fosse; within the embankment there was a platform, depressed so as to leave a circular parapet above its level. Many of these military raths have been found to contain subterranean chambers and circular winding passages, supposed to be used as granaries and armories. They are accounted capable of containing garrisons of from 200 to 500 men; but many of the fortresses mentioned from age to age in our annals were mere private residences, enclosing within their outer and inner walls space enough for the immediate retainers and domestics of the chief. Although coats of mail are mentioned in manuscripts long anterior to the Norman invasion, the Irish soldiers seem seldom or never to have been completely clothed in armour. Like the northern _Berserkers_, they prided themselves in fighting, if not naked, in their orange coloured shirts, dyed with saffron. The helmet and the shield were the only defensive articles of dress; nor do they seem to have had trappings for their horses. Their favourite missile weapon was the dart or javelin, and in earlier ages the sling. The spear or lance, the sword, and the sharp, short-handled battle-axe, were their favourite manual weapons. Their power with the battle-axe was prodigious; _Giraldus_ says they sometimes lopped off a horseman's leg at a single blow, his body falling over on the other side. Their bridle-bits and spurs were of bronze, as were generally their spear heads and short swords.