Perun vs Ukko

The thunder god of the Kievan Rus', sworn by in treaties and installed at the head of Prince Vladimir's official pantheon in 980 before Vladimir himself had his idol destroyed in 988.

Perun is the best-attested of the Rus' gods. The *Russian Primary Chronicle* has the Rus' swear by him and by their weapons in the treaties of 907 and 945, and again in 971; under 980 he stands first among the six idols Vladimir raises on the hill outside his Kiev palace, with a head of silver and a moustache of gold. Procopius, writing in the 550s, describes the early Slavs sacrificing cattle to an unnamed god who alone is "master of all" and "the maker of lightning" — not a named source for Perun, but read by most historians as the same figure centuries earlier.

The sky and thunder god of Finnish and Karelian tradition, 'highest god' of the runo-songs, whose feast at the spring sowing Agricola condemned in 1551 and whom the Kalevala's heroes and Ilmatar call on in need.

No birth or origin is told; Ukko is the old man of the sky, above all.

Mikael Agricola's list of 1551 includes Ukko, and describes a spring rite: when the sowing was done, Ukko's bowl (*Ukon malja*) was drunk, and Agricola complains of the drunkenness and shameful conduct that went with it. Folk poetry calls him *ylijumala*, the highest god, and addresses him in charms and prayers for rain and against storms; a thunderstorm is still *ukonilma*, 'Ukko's weather', in Finnish. Neolithic stone axes turned up by the plough were called *ukonvaaja* or *ukonkirves*, 'Ukko's wedge' or 'axe', and were believed to be thunderbolts he had hurled.