"Ah, that is easy," answered Lord William. "Thou must fly up and down merrie England, especially where any great mansion is, and thou canst not mistake her. She is the fairest flower of all the fair flowers that that fair land contains. Her skin is white as milk, and the roses on her cheeks are red as blood. And, outside her chamber, by a little postern, there grows a nodding birch tree, the leaves of which dance in the slightest breeze, and thou must perch thereon, and sing thy sweetest, when she goes with her sisters and maids to hear Mass in the little chapel." That night, when all the country folk were asleep, a gay gos-hawk flew out from a window in the square tower, and sped swiftly through the quiet air, on and on, above lonely houses, and sleeping towns, and when the sun rose it was still flying, hovering now and then over some great castle, or lordly manor house, but never resting long, never satisfied. Day and night it travelled, up and down the country, till at last it came one evening to a great mansion on the borders of Wales, in one side of which was a tiny postern, with a high latticed window near it, and by the door grew a birch tree, whose branches nodded up and down against the panes. "Ah," said the gos-hawk to itself, "I will rest here." And it perched on a branch, and put its head under its wing, and slept till morning, for it was very tired. As soon as the sun rose, however, it was awake, with its bright eyes ready to see whatever was to be seen. Nor had it long to wait. Presently the bell at the tiny chapel down by the lake began to ring, and immediately the postern opened, and a bevy of fair maidens came laughing out, books in hand, on their way to the morning Mass. They were all beautiful, but the gay gos-hawk had no difficulty in telling which was his master's love, for the Lady Katherine was the fairest of them all, and, as soon as he saw her, he began to sing as though his little throat would burst, and all the maidens stood still for a moment and listened to his song. When they returned from the little chapel he was still singing, and when Lady Katherine went up into her chamber the song sounded more beautiful than ever. It was a strange song too, quite unlike the song of any other bird, for first there came a long soft note, and then a clear distinct one, and then some other notes which were always the same, "Your love cannot come here; your love cannot come here." So they sounded over and over again, in Lady Katherine's ears, until the roses on her cheeks disappeared, and she was white and trembling. "To the dining-hall, maidens; tarry not for me," she said suddenly. "I would fain be alone to enjoy this lovely song." And, as the fresh morning air had made them all hungry, they obeyed her without a moment's thought. As soon as she was alone she ran to the window and opened it, and there, just outside, sat a gay gos-hawk, with the most beautiful plumage that she had ever seen.