After gaining access to Manannan's spellbook, The Sorcery of Old, Gwydion was able to prepare this spell, though he held onto the sleeping powder rather than using it immediately. After being taken captive by pirates, Gwydion cast the spell to put the crew to sleep once they reached the shores of Daventry, allowing him to escape.
This spell will cause anyone within about 50 paces in any direction of the sorcerer to fall into a deep sleep. How long it lasts who knows. Few stay around long enough to see their former captors recover from the narcosis. It is claimed in some texts that the spell was revised into its present form by a priestess of Isis attached to the court of Cleopatra, Goddess and Queen of AEgypt in ancient times. Cleopatra appears to have been extremely fond of revels and feasts on her royal barge, she and her guests floating on the Nile in fogs of forced gaiety. Although Cleopatra was famed through all quadrants of the world for her beauty, wit, and passion, likewise was she also famed for throwing terrible and tawdry parties. It was to escape one of these sad and sordid debacles that the great sorceress began work on the spell. When her experiments were complete, she prepared her ingredients, concealed them within a pouch, and secreted them aboard the boat. Not wanting to remain on the barge a moment longer than necessary, fearing both the loss of her mind and her virtue, she hastened to the supply hold as quickly as she could sneak below deck. After murmuring a soft prayer, she cast her sorcery and escaped. It is also said that when the royal yacht returned to Memphis from whence it started, all aboard were fulsome in their praise of the excursion saying, "ye and verily, a wondrous and funfilled time was had by all. We must have, since we can't remember anything at all of what happened!"