The Klingon Third Dynasty was a period in Klingon history that was founded following what was known as "The Dark Time".
Because the true Imperial bloodlines were cut at the end of the Second Dynasty, a new group of Klingons were given the titles and names of the original Imperial Family in order to create the illusion of an unbroken line. Among the members of the third dynasty were replacements for Reclaw and Shenara. (DS9: "You Are Cordially Invited")
A line from the script of the episode, which did not make it on screen, placed the Year of Kahless 152 in this dynasty.
claimed her twenty-third maternal grandmother to have lived during the beginning of the Third Dynasty, its timeframe must have been several hundred years before the 24th century.