in the prose saga of the fall of gondolin that was to be , begun probably in 1951 , my father recounted the journey of tuor and his elvish companion , voronwe , who guided him ; and on the way , alone in the wilderness , they heard a cry in the woods : and as they waited one came through the trees , and they saw that he was a tall man , armed , clad in black , with a long sword drawn ; and they wondered , for the blade of the sword also was black , but the edges shone bright and cold .