Hill of Tara Hill of Tara (Hill of Kings) is an archaeological complex located near the River Boyne. It contains a number of ancient monuments and mounds. Historians suggested that from the time of the first Celtic influence until the 1169 invasion of Richard de Clare, the Hill of Tara was the island's political and spiritual capital. The significance of the Hill of Tara predates Celtic times, suggesting that it was used as an occasional meeting place. There were no large defensive works. The earliest records attest that high kings were inaugurated there. Archaeologists identified pre-Celtic monuments and buildings dating back to the Neolithic period around 5,000 years ago. One of these structures, the Mound of the Hostages, has a short passage which is aligned with sunset on the true astronomical cross-quarter days of November 8 and February 4, the ancient Celtic festivals of Samhain and Imbolc. Both the Hill of Tara as a hill and as a capital seems to have political and religious influence, which diminished since St. Patrick's time.