==Trivia==
* [[Eric Kripke]] said that "We were airing on Thursdays & needed a new character name. I googled "Angel of Thursday" (for luck): got Castiel." [https://twitter.com/therealKripke/status/667029603685240833 source].* [According to [http://www.ascension-research.org/davidson.html "A Dictionary of Angels: Including the Fallen Angels"] (ISBN-13: 978-0029070529), Castiel is an "Angel of Thursday" in the occult lore. Crowley refers to Cas as "The Angel of Thursday" in [[6.20 The Man Who Would Be King]]. He also comments that it isn't Castiel's day; this may refer to the show having been moved to Fridays. Castiel's name is first mentioned in the season three episode [[3.06 Red Sky at Morning]] during the graveyard scene where Sam reads aloud a summoning ritual from his [[John Winchester|father's]] journal. He speaks the names of several angels during the ritual, and one of them is Castiel.
* [[Misha Collins]] reports that "Kripke wanted to base the look of the character on the comic book character ‘Constantine’" ([http://eclipsemagazine.com/hollywood-insider/6692/hollywood-insidersupernatural%E2%80%99s-angel-of-thursday-%E2%80%93-chatting-with-misha-collins-about-castiel/ Source]).
* There was great secrecy around the introduction of the character. When the role was being cast it was advertised as being for a demon. It was only at the audition that Misha found out Castiel was an angel. [http://www.scribd.com/doc/3641762/Castiel Read the casting sides for Castiel.]
* The show's writers spell the nickname "Cass" ([http://www.scribd.com/doc/73893258/The-Rapture-Network-Draft Source]). In fandom, and particularly in [[fanfiction]] it is almost exclusively spelled "Cas."
* On the [[Season 4 DVD]] the English subtitles call him "Cass" and other times it's "Cas."
* According to [http://www.ascension-research.org/davidson.html "A Dictionary of Angels: Including the Fallen Angels"] (ISBN-13: 978-0029070529), Castiel is an "Angel of Thursday" in the occult lore. This may be a reference to the fact that ''[[Supernatural]]'' aired on Thursday nights on The CW when the character was introduced. Crowley refers to Cas as "The Angel of Thursday" in [[6.20 The Man Who Would Be King]]. He also comments that it isn't Castiel's day; this may refer to the show having been moved to Fridays.
* There is a municipality in Switzerland called Castiel. Its coat of arms is Saint George killing a dragon. It looks similar to Michael fighting a dragon. This image has appeared in paintings in [[2.13 Houses of the Holy]] and [[4.22 Lucifer Rising]].