Zadok (Hebrew: Tzadok צדוק, meaning "Righteous") was a priest descended from Eleazar the son of Aaron. He aided King David during the revolt of his son Absalom, and was consequently instrumental in bringing King Solomon to the throne. After Solomon's building of The First Temple in Jerusalem, Zadok was the first High Priest to serve there.
The prophet Ezekiel extols the sons of Zadok as staunch opponents of paganism during the era of its pagan worship and indicates their birthright to unique duties and privileges in the future Third Temple (Ezekiel 42:13, 43:19).
Read more about Zadok: Hebrew Bible, Dead Sea Scrolls, In Rabbinical Literature, The Zadokite Dynasty, Other Theories