but apologized for their inability to assist him in his demands. Regardless, Trịnh Tạc began the offensive by sending an army to break the Tran Ninh wall along the Nhật Lệ River, but the southerner prince Ton That Hiep sent general Nguyen Huu Dat to reinforce the wall and successfully repelled the northerner attack. The costly campaign ended inclusively, and the lord turned to attack the Mạc family in the north. In 1677 his army finally destroyed the last Mạc remnants in Cao Bang province, forcing the Mac to flee to Southern China, where they were captured by the Qing army in 1683. Political career During the Vinh Tho era (1658–1662), Trịnh Tạc and his scholars had reestablished and revived the civil bureaucratic government that had been set up by king Le Thanh Tong in the fifteenth century, by resetting population registers, taxation, reconstructing dykes and roads, reopened state-sponsored schools and civil examinations. In the beginning of his reign, Trịnh Tạc continued his father's friendly view toward Christian missionaries and Christian communities. However, his officials and advisors who saw the missionaries as foreigners and spies for the Nguyễn regime in Hue, gradually changed his belief. In June 1658, the Swiss superior Onuphre Borges was ordered to recall all the Jesuit missionaries in Hanoi to embark for Macao. While Trịnh Tạc threatened to prohibit Christianity, he continued to tolerate the Jesuits and their converts. In 1662 he declared Taoism and Buddhism the state religions while outlawing Christianity. Also in November of the same year the old king Le Duy Ky died, and Trịnh Tạc selected 10-year-old Prince Le Duy Vu as king. In 1663 the Jesuits were banished from north Vietnam. On 13 July 1669 he prohibited foreign vessels to arrive Hanoi, and instead they were docked in Pho Hien, along the Red River. Trịnh Tạc welcomed the first French ship Compagnie des Indes Orientales led by Lambert de la Motte, two priests Jacques de Bourges (1630–1714) and Gabriel Bouchard in Pho Hien. He permitted the French to build a factory at Pho Hien in hope that he would receive more European cannons and to counter the Dutch and Portuguese businesses in Tonkin. In 1672 he allowed the English East India Company to open a factory in Hanoi. Because of his failed campaign in the same year, Trịnh Tạc turned his anger against the Jesuits and expelled Giovanni Filippo Marini in