The religious ceremonies of the Scandinavians were simple. Their worship, like that of the followers of Zoroaster, was at first held in the open air; but in later times they erected temples, some of which were quite splendid. There were three great festivals in the year. The first was at the winter solstice, and on the longest night of the year, which was called the Mother Night, as that which produced the rest. This great feast was called Yul, whence comes the English Yule, the old name for Christmas, which festival took its place when the Scandinavians became Christians. Their festival was in honor of the sun, and was held with sacrifices, feasting, and great mirth. The second festival was in spring, in honor of the earth, to supplicate fruitful crops. The third was also in the spring, in honor of Odin. The sacrifices were of fruits, afterward animals, and occasionally, in later times, human beings. The people believed in divine interposition, and also in a fixed destiny, but especially in themselves, in their own force and courage. Some of them laughed at the gods, some challenged them to fight with them, and professed to believe in nothing but their own might and main. One warrior calls for Odin, as a foeman alone worthy of his steel, and it was considered lawful to fight the gods. The quicken-tree, or mountain-ash, was believed to possess great virtues, on account of the aid it afforded to Thor on one occasion. Beside the priests, the Northern nations had their soothsayers. They also believed that by the power of runes the dead could be made to speak. These runes were called galder, and another kind of magic, mostly practised by women, was called seid. It was thought that these wise women possessed the power of raising and allaying storms, and of hardening the body so that the sword could not cut it. Some charms could give preternatural strength, others the power of crossing the sea without a ship, of creating and destroying love, of assuming different forms, of becoming invisible, of giving the evil eye. Garments could be charmed to protect or to destroy the wearer. A horse's head, set on a stake, with certain imprecations, produced fearful mischief to a foe.[331] Very few remains of temples have been found in the North. But (as Laing remarks in his "Sea-Kings of Norway") the most permanent remains of the religion of Odin are found in the usages and languages of the descendants of those who worshipped him. These descendants all retain, in the names of Wednesday, Thursday, and Friday, the recollections of the chief gods of this mythology. Mara (the nightmare) still torments the sleep of the English-speaking people; and the Evil One, Nokke (so says Laing), is the ancestor of Old Nick.