The Lebor Gabála Eireann, or Book of Invasions tells of the coming to Ireland of the Tuatha Dé Dannan. As this tribe struggled to establish themselves upon the land and then defend it from invasion and war, there was one among the heroes who offered to do all that any other could volunteer. The lore tells us that they called him An Dagda as he was their Great God of druidry and magic.
What deeds could there be had if there were no one to record and remember them? Who would recall the names of the slain in times to come if not for the observation of their passing? Who could stand and gaze into the harming and slaying with a will to see, with a mind to recall every detail, and with a heart that could not be broken?