In 1570, Trịnh Kiểm died and was succeeded by his second son Trịnh Tùng. Tùng was a very vigorous leader and he captured Hanoi from the Mạc Emperor in 1572. However, the Mạc Emperor (Mạc Mau Hop) recaptured the city the next year. The war continued at a low level for two decades, the Trịnh gradually gaining strength, the Mạc gradually weakening. In 1592, Tùng launched a major invasion and again captured Hanoi. This time the Royal (Trịnh) army captured the Mạc Emperor and executed him. Over the next few years the remaining Mạc armies were defeated in battles. In this "mopping-up" campaign, the Trịnh were helped by the Nguyễn army.