What is the origin of adios?

Adiós is [http://en.wikipedia.org/wiki/Spanish_language Spanish] for "goodbye". Literally translated, the Word is the contraction of "a" (to) and "DiOS" (God), from the old Spanish phrase "A DiOS vais" ("You're going to God", meaning to the Kingdom of Heaven), which appears in the novel [http://en.wikipedia.org/wiki/Don_Quixote Don Quixote]. It is roughly equivalent to the English phrase "[http://en.wiktionary.org/wiki/Godspeed Godspeed]" or "Go with God" ("Vaya con DiOS")