sentences:  The Thuận Thiên sword was used to affirm the legitimacy of Lê Lợi as the Vietnamese leader in the revolution against the Ming occupation and associated with Lê Lợi the rightful sovereignty of Vietnam.In Vietnam, the legitimacy of the monarch is known as the mandate of heaven.Lê Lợi revolted in 1418 against the Ming Dynasty, who had invaded and occupied Vietnam in 1407.