Human beings are relatively new inhabitants of Ireland. The oldest evidence of them, near Coleraine, dates to around 7,200 B.C.E. Celtic-speaking Gaels, skilled with horses and iron weapons, controlled the island by the beginning of the Christian era.

Ireland escaped Roman conquest and invasion by Germanic tribes. Not until the end of the eighth century did Ireland attract the attention of aggressive outsiders, the Vikings.

A century after they overwhelmed England, the Normans came to Ireland. They quickly overran much of the south and west, yet Norman hold of Ulster's coastlands remained precarious. By the late fifteenth century, all Ulster, save the castle of Carrickfergus, had fallen outside the English Crown's control.

The sixteenth century witnessed seismic change. England became a powerful, centralized state under Tudor monarchs. It also became Protestant, so its rulers could not afford to allow Catholic powers--Spain in particular--to threaten the realm from the west by making common cause with disaffected Irish.