Thunder god and supreme deity of the East Slavic Kievan Rus' pantheon as installed by Vladimir at Kiev in 980 CE; the central male-warrior-thunder deity of the broader Slavic polytheistic pantheon. The foundational Indo-European thunder-deity-and-oak complex: Perun cognate with Lithuanian Perkūnas, Old Norse Fjǫrgynn, Vedic Parjanya, all from PIE *per(k)w- "to strike" (also yielding Latin quercus "oak"). Procopius (mid-6th c.) describes the early Slavs as venerating "the maker of lightning as the only lord of all" — the foundational Greek-language attestation of the Slavic thunder-deity supremacy. The Primary Chronicle's description of Vladimir's 980 CE Perun cult-statue at Kiev (silver head with gold mustache) is the most-detailed Slavic polytheistic cult-iconography preserved in textual record. Vladimir's 988 CE destruction of the Perun cult-statue (dragged behind a horse to the Dnieper and thrown in) is the foundational suppression-of-paganism event of Slavic Christianization. The Perun-Veles cosmic opposition (Jakobson 1969) — Perun as sky-thunder-warrior vs. Veles as chthonic-cattle-magician — is the foundational structuring antagonism of Slavic polytheistic theology, with the basic mythologem (thunder-god strikes serpent-or-cattle-thief) preserved across folk-tradition material.