In Galician, Northern Portuguese and Asturian tradition, the rainbow is called “arco-da-velha” (The old woman’s arch, in English), because people believed the Old Woman Goddess (“velha”) was responsible for their appearance. The Old Woman is Cailleach.
In Irish, Gallaecian and Scottish mythology, Cailleach, also know as Cailleach Bheur, is a divine hag, a creatrix, and possibly an ancestral deity or deified ancest. Her function would be to protect all animals in Autumn and Winter and take care of Nature, although it is believed that she was also the spirit of Winter, which did not allow nature to develop freely.

According to ancient beliefs, Cailleach is the mother of all gods and goddesses. In partnership with the goddess Brìghde, she is a seasonal deity or spirit, ruling the Winter months between Samhainn (1st of November) and Beltane (1st of May), while Brìghde rules the Summer months between Beltane and Samhainn.

Photo: The Arco-da-Velha over the cities of Porto and Gaia, Ancient Portus Cale or Portus Gale, Roman designation for this are of Northern Portugal where the native Celts worshiped the Goddess Cailleach.
Photo Credits : Manuel Gonçalves

Gallaecian Celtic Culture, GCC 02/06/2018