(Sept 7, 2023) Slavic culture originated around the Dnieper. As Greek/ Byzantine power waned they migrated south into the Balkans and north into Russia. By 600 CE this split in culture was becoming linguistically obvious.
Today the south Slavs include the Bosniaks, Bulgarians, Croats, Macedonians, Montenegrins, Serbs and Slovenes. They are different from the North (West and East) Slavs. Today, groups which speak West Slavonic languages include the Poles, Czechs, Slovaks, and Sorbs. The groups which speak the East Slavonic languages are the Belarusians, Russians, Rusyns, and Ukrainians.
Excellent video by M. Laser History.
(August 18, 2024) The earliest information comes from early Medieval Christian texts. They had no bardic tales as found in Celtic and Nordic lands. The deities which have some sort of additional contextual information in the surviving texts are:
God Perun - As Akkadian P.R it means "Opener of Eagle-vultures." He was the creator of lighting.
God Svarog - As Akkadian Ṣ.UR.G it means "Activator of Dawn's Energy." A textual commentary from 1100's describes him as god of the sun.
God Svarozić - As Akkadian Ṣ.UR.Š it means "Activator of Dawn's Similar-things." (ić typically means "son" in Slavic languages as one who is similar to his father). A textual commentary from 1100's describes him as a blacksmith or a god of fire.
God Dazbog - As Akkadian D.ZB.G it means "Manifestor of Pumping's energy." in which pumping was a word used to describe the force moving fluid flows including fertility-fluids which transported life powers from the divine realm to earth.
Goddess Mokoš - As Akkadian it M.K.Š it means "Fertility-Fluid's Involvements with Similar-things." She was a fertility goddess probably combining the aspects of Druid Ayu and Asher.
Their main spring festival was Rusalia or Rus - alia. RaṢu in Akkadian means "life-powers."