The opening hour examines whether there are kernels of truth in the legends of mighty warriors like Cu Chullain and immortal rulers like Queen Maeve. Are the Irish even Celtic? Archeologists have found little evidence. The program also delves into the vast burial mounds that dot Ireland's verdant landscape, the climatic Bronze Age disaster that changed Ireland forever, the ensuing era of prosperity that transformed Ireland into Europe's richest nation, the role of Rome in Ireland, and the founding of a new kingdom in Scotland by Irish warlords who would ultimately take over the entire country.

The second hour focuses on the rise of Christianity in Ireland between the 5th and 9th centuries A.D. During this era, missionaries spread the faith, creating compelling and powerful scholarship, theology, and art. Their efforts illuminated the Dark Ages that plagued Europe after the fall of the Roman Empire. This episode also depicts the transition from paganism to Christianity and its ramifications. Above all, the program examines how the power of writing allowed the church to control history in its zeal to transform the pagan Irish.

The final installment chronicles the centuries of war leading up to the Norman invasion. This was an era defined by power-hungry Vikings, Irish kings preoccupied with their own dynastic battles, the reign and murder of the high king Brian Boru, and Rome's campaign to stamp out corrupt practices within the Celtic church. "Warlords" explores 150 years of rivalry between various factions seeking control of Ireland, and the arrival and interference of England's King Henry II. This is the great watershed of events as the English throne now claims supremacy over Ireland and the Irish -- a complex and bitter legacy whose repercussions continue to the present day.