etymologies have been suggested). Blodeuwedd falls in love with a hunter, Gronw Pebr, and they plot to kill Lleu. Blodeuwedd tricks Lleu into revealing the means by which he can be killed, but when Gronw attempts to do the deed Lleu escapes, transformed into an eagle. Gwydion finds Lleu and transforms him back into human form, and turns Blodeuwedd into an owl, renaming her Blodeuwedd and cursing her. Gronw offers to compensate Lleu, but Lleu insists on returning the blow that was struck against him. Gronw pleads to be allowed to hide behind a rock when he attempts to kill him. Lleu agrees. He kills Gronw with his spear, which is thrown so hard it pierces him through the stone he is hiding behind. Cad Goddeu A large tradition seems to have once surrounded the Battle of the Trees, a mythological conflict fought between the sons of Dôn and the forces of Annwn, the Welsh Otherworld, and seemingly connected to the Fourth Branch of the Mabinogi. Amaethon, one of the sons of Dôn, steals a white roebuck and a whelp from Arawn, king of the otherworld, leading to a great battle. Gwydion fights alongside his brother and, assisted by Lleu, enchants the "elementary trees and sedges" to rise up as warriors against Arawn's forces. The alder leads the attack, while the aspen falls in battle, and heaven and earth tremble before the oak, a "valiant door keeper against the enemy". The bluebells combine and cause a "consternation" but the hero is the holly, tinted with green. A warrior fighting alongside Arawn cannot be vanquished unless his enemies can guess his name. Gwydion guesses the warrior's name, identifying him from the sprigs of alder on his shield, and sings two englyns: "Sure-hoofed is my steed impelled by the spur; The high sprigs of alder are on thy shield Native tales The Dream of Macsen Wledig This account is so different from Geoffrey of Monmouth's account of Maximian (as Geoffrey calls him) in Historia regum Britanniae that scholars agree that the Dream cannot be based purely on Geoffrey's version. The Dream's account also seems to accord better with details in the Triads, so it perhaps reflects an earlier tradition. Macsen Wledig, the Emperor of Rome, dreams one night of a lovely maiden in a wonderful, far-off land. Awakening, he sends his men all over the earth in search of her. With much