Vinalia

...This is thought to be a remnant of the old custom of worshipping this god on the full moon, when the light of the sky is strongest at night. He was worshipped at the wine festival Vinalia because grape growing, which requires ample sunlight, was thought to be under his special protection as the god of light. As the god of thunder, he was also considered the god of all oaths, contracts, and treaties, and it was believed that he would punish those who violated them with lightning.

*Some of the terminology explanations that mention "Vinalia" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…これは，夜でも天の光が最も強い満月の日にこの神をあがめた古い風習のなごりと思われる。ブドウ酒の祭ウィナリアVinaliaで彼があがめられたのも，十分な陽光を必要とするブドウ作りが光明神としての彼の特別の保護下にあると考えられたからであろう。また雷神としての彼はあらゆる誓い，契約，条約などの神ともされ，その違反者を雷で罰すると信じられた。…

※「Vinalia」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報