The potion was to brew for a year and a day. At the end of that time, there were only three precious drops left at the bottom of the cauldron. While Gwion Bach was stirring, the potion popped up and burnt his thumb, which he stuck into his mouth. Realizing at once who Ceridwen was and what she would do to him now that the potion was gone, Gwion Bach fled the lake with Ceridwen on his heels.
Gwion Bach changed into a hare to escape his pursuer. Ceridwen changed into a greyhound. Gwion flung himself into the river and became a trout, Ceridwen changed into an otter and followed him. Gwion leapt from the water and became a swift, soaring through the air. Ceridwen became an eagle and followed him. Gwion flew into a farmer's yard and changed into a grain of wheat and hid himself in a pile of hen-scratch. Ceridwen changed herself into a hen and ate the pile of scratch, devouring Gwion Bach along with the rest of the wheat.
Upon resuming her normal form, she found herself pregnant and devised to kill the traitorous Gwion upon his birth.
But once the child was born, her resolve wavered and she set the infant in a basket on the tide and left him to his fate.
A fisherman who set his traps in one of the inlets of the sea found the child, exclaiming at his appearance with the words, "Radiant Brow!" or, "Taliesin!" and this became the boy's name.
Taliesin became the greatest bard of Wales, and all the bards after him called themselves the Sons of Ceridwen.