 Yeon Gaesomun's second son, Yeon Namgeon, resisted in the face of death, as opposed to his brother's treachery, and fought until the very end.Meanwhile, Yeon Gaesomun's younger brother, Yeon Jeongto, defected to the Silla side.The Tang–Silla alliance mounted a fresh invasion of Goguryeo in 667, aided by the defector Yeon Namsaeng, and in 668, finally vanquished the divided kingdom, which had been plagued by violent dissension, numerous defections, and widespread demoralization following the death of Yeon Gaesomun.