In course of time, however, when the Finns came to have more purified ideas about religion, they called the sky Taivas and the sky-god Ukko.  The word, Ukko, seems related to the Magyar Agg, old, and meant, therefore, an old being, a grandfather; but ultimately it came to be used exclusively as the name of the highest of the Finnish deities.  Frost, snow, hail, ice, wind and rain, sunshine and shadow, are thought to come from the hands of Ukko.  He controls the clouds; he is called in The Kalevala, “The Leader of the Clouds,” “The Shepherd of the Lamb-Clouds,” “The God of the Breezes,” “The Golden King,” “The Silvern Ruler of the Air,” and “The Father of the Heavens.”  He wields the thunder-bolts, striking down the spirits of evil on the mountains, and is therefore termed, “The Thunderer,” like the Greek Zeus, and his abode is called, “The Thunder-Home.”  Ukko is often represented as sitting upon a cloud in the vault of the sky, and bearing on his shoulders the firmament, and therefore he is termed, “The Pivot of the Heavens.”  He is armed as an omnipotent warrior; his fiery arrows are forged from copper, the lightning is his sword, and the rainbow his bow, still called Ukkon Kaari.  Like the German god, Thor, Ukko swings a hammer; and, finally, we find, in a vein of familiar symbolism, that his skirt sparkles with fire, that his stockings are blue, and his shoes, crimson colored.

In the following runes, Ukko here and there interposes.  Thus, when the Sun and Moon were stolen from the heavens, and hidden away in a cave of the copper-bearing mountain, by the wicked hostess of the dismal Sariola, he, like Atlas in the mythology of Greece, relinquishes the support of the heavens, thunders along the borders of the darkened clouds, and strikes fire from his sword to kindle a new sun and a new moon.  Again, when Lemminkainen is hunting the fire-breathing horse of Piru, Ukko, invoked by the reckless hero, checks the speed of the mighty courser by opening the windows of heaven, and showering upon him flakes of snow, balls of ice, and hailstones of iron.  Usually, however, Ukko prefers to encourage a spirit of independence among his worshipers.  Often we find him, in the runes, refusing to heed the call of his people for help, as when Ilmatar, the daughter of the air, vainly invoked him to her aid, that Wainamoinen, already seven hundred years unborn, might be delivered.  So also Wainamoinen beseeches Ukko in vain to check the crimson streamlet flowing from his knee wounded by an axe in the hands of Hisi.  Ukko, however, with all his power, is by no means superior to the Sun, Moon, and other bodies dwelling in the heavens; they are uninfluenced by him, and are considered deities in their own right.  Thus, Paeivae means both sun and sun-god; Kun means moon and moon-god; and Taehti and Ottava designate the Polar-star and the Great Bear respectively, as well as the deities of these bodies.