Mary Morrison returned to China only to die in 1821; Mrs. Milne had died already. Morrison was 39. In 1822 William Milne died, after a brief but valuable missionary life, and Morrison was left to reflect that he alone of the first four Protestant missionaries to China was now left alive. He reviewed the history of the mission by writing a retrospect of these fifteen years. China was still as impervious as ever to European and Christian influence; but the amount of solid literary work accomplished was immense.