Díjūn wéichéng sān ge yuè, shǒujūn shǐzhōng méiyǒu tóuxiáng.
The enemy besieged the city for three months, but the defenders never surrendered.
Tips
usage
守 'to guard' + 军 'troops'. In accounts of battles it pairs with 敌军 'enemy troops' and 援军 'reinforcements'; when the defenders lose a position, it is 失守.