Wherever Jews have been, they have built monuments by using materials common to each region, to serve as a reminder of their presence. Many myths have developed as to who originated, planned, designed, Stonehenge; a popular belief is that a man given the name "Merlin" is responsible; the name is thought to be derived from that of the ancient Celtic sky god, "Myrddin." A Welsh bard states that the whole of Britain before men came was called "Clas Myrddin," or "Merlin's Enclosure," and Merlin is thought to have mentioned three waves of invaders prior to construction beginning on Stonehenge; 1) the Formorians, 2) the Sons of Partholan, and 3) the Nemedians. Mythological records refer to the Fomorians as fierce and dangerous, "gloomy sea-giants, warlike, very troublesome to the entire world." Records also mention the Druids as the creator of Stonehenge, who, as far as we know, never wrote anything themselves, but accumulated evidence indicates they were commonly perceived to be holy men, medicine men, teachers, and judges.