Io & Jove:

Jove concealed himself in fog and raped Io. Juno became suspicious of Jove when she saw the clouds and went to investigate, but Jove turned Io into a beautiful, white heifer before Juno could arrive. Juno asked to have the heifer, and Jove had no choice but to agree in order to keep his secret. Juno still thought that Jove was up to something so she made Argus, who had one hundred eyes, watch the heifer. All the while, Io's father mourned for her. Jove could not endure Io's suffering as a cow so he instructed Mercury to kill Argus. Mercury tried to put Argus to sleep with a song, but he cannot make all of Argus's eyes shut at the same time. Then, Argus asked how the pipe instrument had come to be invented. Thus, Mercury began the story of Syrinx.