land, the earth', and she could have originally been the mistress of the wooded mountains, the personification of what appears in Gothic as ('wooded mountain'). Additionally, the Baltic tradition mentions a perpetual sacred fire dedicated to and fuelled by oakwood in the forests or on hilltops. Pagans believed that Perkūnas would freeze if Christians extinguished those fires. Words from a stem are also attested in the Hittite ('rock, cliff, boulder'), the Avestan ('mountains'), as well as in the Sanskrit goddess and the epithet ('lord of mountains'), attached to her father . Stony skies A term for the sky, , denoted both 'stone' and 'heaven', possibly a 'heavenly vault of stone' akin to the biblical firmament. The motif of the stony skies can be found in the story of the Greek Akmon ('anvil'), the father of Ouranos and the personified Heaven. The term was also used with the meaning 'thunderbolt' in Homeric and Hesiodic diction. Other cognates appear in the Vedic ('stone'), the Iranian deity ('stone, heaven'), the Lithuanian god (mentioned alongside himself), and also in the Germanic (, ) and (cf. Old Norse: , which could mean 'rock, boulder, cliff' or 'hammer'). is described in a 16th century treatise as a , 'a sizeable stone', which was still worshipped in Samogitia. Albanians believed in the supreme powers of thunder-stones (kokrra e rrufesë or guri i rejës), which were believed to be formed during lightning strikes and to be fallen from the sky. Thunder-stones were preserved in family life as important cult objects. It was believed that bringing them inside the house could bring good fortune, prosperity and progress in people, in livestock and in agriculture, or that rifle bullets would not hit the owners of the thunder-stones. A common practice was to hung a thunder-stone pendant on the body of the cattle or on the pregnant woman for good luck and to contrast the evil eye. The mythological association can be explained by the observation (e.g., meteorites) or the belief that thunderstones (polished ones for axes in particular) had fallen from the sky. Indeed, the Vedic word is the name of the weapon thrown by Indra, Thor's weapon is also called , and the thunder-stone can be named ('Perkuna's stone') in the Lithuanian tradition. Scholars have also noted that and are said to strike rocks instead of oaks in some themes of the Lithuanian and Belarusian folklores, and that the