The 'circle casting' is basically just a Wiccan term for the Ritual of the Pentagram, which originates from the Victorian occult society Golden Dawn. The main difference compared to the generic pentagram ritual is that Wiccan circle castings, as the name suggests, usually include the distinct act of tracing a circle around the working space (whereas in the pentagram ritual a circle is implied as the magician moves his tool from quarter to quarter). It is generally used as the opening part of a ritual, and could be followed by more specific acts of magick, celebration of a particular holy day, or merely simple meditation or prayer.
- Start by preparing the altar, if you use one. Light a candle (or several), while saying: 'Assist me to build, as the mighty ones willed, an altar of praise, from beginning of days.'
- Trace a circle around you with your working tool (knife, wand or other 'Pointy Thing'), while saying: 'Be this, as of yore, the shrine I adore!'
- Returning to your initial position, make an appropriate gesture and say: 'Invoked in this sign, the power divine!'
- Now, trace a pentagram in each of the four quarters (beginning from the east and proceeding clockwise), while saying: 'By rushing wind, by leaping fire, by flowing water, by green earth!'
- Returning again to your initial position, say: 'Pour me the wine of my desire, from out thy cauldron of rebirth!' (If you have a cup or chalice with drink on your altar, you may take a sip at this point.)
The original version of the third line is 'Invoked in this sign, the Goddess divine', which obviously invokes a more Wiccan feel. I've on occasion replaced it with a rhyme of my own: 'The welcoming feast, for Muse and for Beast', to invoke both Goddess and God energies. (This line is of course based on my own interpretations of the deities, and may not sound very mainstream Wiccan. Note that the 'Beast' here refers to the Horned God as a nature deity, not to any biblical demons.) In Wiccan use the circle casting could be followed by a chant such as the Witches' Rune.
This is a slightly darker version of the incantation I devised for use with an 'Invocation of Darness' I wrote: 'Be this, as of yore, the shrine I adore. An altar of praise from beginning of days. A welcoming feast for ravening beast. Invoked in this sign the Darkness divine. By raging wind, by leaping fire, by falling rain and by cold earth, pour me the ichor of desire, from out thy organs of rebirth.' I removed the part that calls for assistance, since that doesn't necessarily go so well with left-hand path ideas. Most of the incantation is still fairly neutral and nature-oriented, of course, though 'ichor' hearkens back to pulp horror (even if the word originally meant the blood of gods), and associated with 'organs of rebirth' ('organs' in plural as I didn't want to associate it with any particular sex) has perhaps a sexual feel to it.