The idea of Maiden, Mother and Crone don't work well with the Celtic beliefs. There is no true triple goddess in mythology, it is a new age concept created by the poet Robert Graves.
I personally teach my daughter, however, that the Goddess (Mother Earth) gives birth to the Sun and becomes the Great Mother. The Goddess isn't the most important aspect of Yule, the spotlight is on the Sun's death and rebirth. The Goddess is focused on during the sabbats that land in the beginning of the month. The Solstices are always male centered celebration (those celebrated in the middle of the month). After the birth of the Sun, depending on the person, the Goddess goes to sleep or grows old and dies until Spring. So I would say she is the Mother during Yule because a crone doesn't give birth.
And what I mean by no true triple goddess, is there is no goddess of maiden, mother and crone "faces". The goddesses who have three faces aren't like that. You can't find anything in mythology that actually supports a supreme goddess of three faces. The only thing in mythology that comes close is the Moirai (Fate sisters) but they were separate women, not one being.
Haha, I wrote that in a rush. Still a few more typos there that are bugging me but oh well. I still wish there was an edit feature on the forums...
But I was a bit bored (it being 2am with no one on SOM) and thought I would look around the web for Neko, I found this!
http://whisperingworlds.com/wiccan/yule.php
Maiden, Mother, and Crone refer to the three aspects of the yearly cycle. Maiden is birth, rebirth, rejuvenation, cleansing. In other words spring. Mother is the aspect of growth and development. Caring and nurturing. Summer as it enters fall. Crone is the end of the cycle and the rebirth of the new. The possession of the great wisdom of life and experience. The onset of winter and then the rebirth again into spring. Since Yule falls into the end of the year then the Goddess would be in the crone stage.
@ whiterav3n, i know, i was writing a little something when i lite the three candles on the Yule log, i had one for the oak kings rebirth, then i needed one for the goddess, but i wanted to say which one she was right now. [i mean, at that point] i don't follow the god and goddess as much anymore, but a good portion of my coven does, so we try and generalize our ceremony then when it comes to personal moments like meditation, or personal offerings to our deities, or spell casting that's when we go for our own belief.
@ Dillon13, that's what was confusing me in a nutshell, it's the end of the year, so it's crone, but she gives birth to the god [sun] so rebirth should be maiden [possibly mother] .
@ wizhard, depends on what you belief and the holiday. Yule is a God based holiday, celebrating the rebirth of the sun. the god, as some believe, is reborn in the morning, and it's the goddess who gives birth to him. she's really minor in this holiday, think of Santa Clause and Mrs. Clause, she's there, people like her, there's a story about her saving Christmas, but the big excitement and festivities center around her husband. i personally follow Egyptian deities, i know Imbolc is a Brigit holiday historically, and as midsummer approaches i belief Amaterasu [Japanese] or Juno [Roman] are worshiped goddesses.
I look at it as the aspect of four not three. I see rebirth as it's own aspect but really it has roots in all three aspects. For we are always rebuilding and renewing. Therefor birth would be a beginning yet rebirth would be not an end for a cycle has no end it just starts over again. Maiden represents birth or youth. Crone represents death but in the cycle of life there is no end. Just a transition to something new. That's why I think that reincarnation in some forms is a valid thought. If you really want to think about it Maiden goes through rebirth and becomes Mother. Mother goes through rebirth and becomes Crone. Crone leaves behind the limitations of old age and death and goes through rebirth into the next stage. Therefor becomes maiden again.
I agree completely with Rav3n on the focus of Yule and nonexistence of a triple goddess. Yule is also Dies Natalis Sol Invicti to those who practice the Religio Romana (Religion of Rome). Literally that translates into "Day of Birth of the Unconquerable Sun". The focus on that time of year shouldn't be the goddess but instead the god.
I was taught the Mother is at form during Yule in order to symbolically give birth to the Sun (the God). Then in spring she is the Maiden, during the spring and Early summer she is unioned with the God and on Samhain she is both Mother and Crone. The God impregnates the Maiden before he moves on to Summerland, the Crone is there also but representing the Mother from last year who has grown old. Although, since this is all harshally symbolic, it varies Wiccan to Wiccan and Coven to Coven. Choose which on you find makes the most sense to you.