Macha is horse goddess from Irish Celtic Mythology. She is very closely related to Epona in Britain and Gaul and Rhiannon in Wales. Horse goddesses were highly worshipped in Celtic lands because of the importance of horses to their tribal society. She was also a goddess of fertility and skill, particularly skill at armed contest. Worship of Macha is believed to have centered around the Ulster area of Northern Ireland
One of the legends of Macha that I have read concerns her race against the king's chariot and horses. Her husband, Crunniuc, had drunkenly boasted that his wife was faster then the king's horses and the challenge was accepted by the king. Macha was nine months pregnant and felt labor pains overcome her as she was brought before the king at the gathering. She pleaded with the warriors to spare her until her children were born, but they refused, stating that unless she ran, Crunniuc would be killed. So she ran, giving birth to a son and daughter at the end of the race. But, she cursed the men that watched the race and for five days and nights the men bore labor pains.