In AD 498 a young monk named Kevin arrived in the Glendalough Valley looking for somewhere to kick back, meditate and be at one with nature. He pitched up in what had been a Bronze Age tomb on the southern side of the Upper Lake and for the next seven years slept on stones, wore animal skins, maintained a near-starvation diet and – according to the legend – became bosom buddies with the birds and animals. Kevin's ecofriendly lifestyle soon attracted a bunch of disciples, all seemingly unaware of the irony that they were flocking to hang out with a hermit who wanted to live as far away from other people as possible. Over the next couple of centuries his one-man undertaking mushroomed into an established settlement and by the 9th century Glendalough rivalled Clonmacnoise as the island's premier monastic city. Thousands of students studied and lived in a thriving community that was spread over a considerable area.
Inevitably Glendalough's success made it a key target for Viking raiders, who sacked the monastery at least four times between 775 and 1071. The final blow came in 1398, when English forces from Dublin almost destroyed it. Efforts were made to rebuild and some life lingered on here as late as the 17th century when, under renewed repression, the monastery finally died.