Which era is the Duke of Zhou in Duke of Zhou?

The Duke of Zhou in The Duke of Zhou is Ji Dan, whose surname is Ji Mingdan. He is the fourth son of Zhou Wenwang, the younger brother of King Wu, and a famous politician in ancient China. He assisted Zhou Wuwang in two expeditions to Zhou Wang and ruled the world with rites and music. Because of its fief in Zhou, Jue is the main, so it is called Duke of Zhou. Duke Zhou said to himself in the spit: "Son of King Wen, brother of King Wu, uncle of King Wang; I am also in the world, and I am not a light in the world. However, if you hold it for three times and vomit for three times, you still fear losing the people of the world. "