Task: Question Generation
Input (English): Passage: The former ruling dynasty of Đại Việt, the Trần, had relations with the Yuan and Ming Empire as a tributary. However, in 1400, Hồ Quý Ly deposed and massacred the Trần house before usurping the throne. After taking the throne, Hồ renamed the country from Dai Viet to Dai Ngu. In 1402, he abdicated the throne in favor of his son, Hồ Hán Thương . In October 1404, Trần Thiên Bính  arrived at the Ming imperial court in Nanjing, claiming to be a Trần prince. He notified the court of the treacherous events that had taken place and appealed to the court for the restoration of his throne. The Yongle Emperor of the Ming Empire issued an edict reprimanding the usurper and demanding the restoration of the Tran throne, a pretext to the annexation of Vietnam. As the party crossed the border into Lạng Sơn, Hồ's forces ambushed them and killed the Trần prince that the Ming convoy were escorting back. In the winter of 1406, the Ming armies began their invasion. Zhang Fu and Mu Sheng departed from Guangxi and Yunnan respectively to launch a pincer attack into enemy territory. On 19 November 1406, they captured the two capitals and other important cities in the Red River Delta.  Hồ Quý Ly and his son were captured on 16 June 1407, they were caged and brought as prisoners to the Yongle Emperor in Nanjing.
Output (English): When did the Ming armies capture the two capitals in the Red River Delta?