Cup of Vows
(The). It used to be customary at feasts to drink from cups of mead, and vow to perform some great deed worthy of the song of a skald. There were four cups: one to Odin, for victory; one to Frey, for a good year; one to Niörd, for peace; and one to Bragi, for celebration of the dead in poetry.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894