Calan Gaeaf

Calan Gaeaf is the name of the first day of winter in Wales, observed on 1 November. The night before is Nos Galan Gaeaf, an Ysbrydnos when spirits are abroad. People avoid churchyards, stiles, and crossroads, since spirits are thought to gather there.

Children and women would dance around a village fire and, during this process, everyone would write their names on rocks and place them in and around said fire. When the fire started to die out they would all run home- whereas if they stayed, 'Yr Hwch Ddu Gwta' (a bad omen that took the form of a tailless black sow with a headless woman) would devour their souls. It is believed that the traditions and stories surrounding 'Yr Hwch Ddu Gwta' were survived by local parents as a means of ensuring their children would return home safely and as early as possible on this cold, dark night. One particular rhyme shows how the last child out on Nos Calan Gaeaf was at risk of being eaten by the fearsome beast:

Adre, adre, am y cynta', Hwch ddu gwta a gipio'r ola'.

(Home, home, on the double, The tailess black sow shall snatch the last [one].)

The following morning, all the stones containing villagers' names would be checked. If, however, a stone was missing, the person who wrote their name on the stone would die within one year.

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Wikipedia