the strongest garrison actually doesn't include archers because they die quickly to enemy archers and hardly do any damage compared to the large army your enemy will have. the best is swords and ballistae because swords are better at tanking archers and therefore will keep your ballista alive longer to do more damage to the enemy siege machines because enemy archers have to kill all the swordsmen before being able to damage your ballistae, and the most ideal ratio between swords to ballistae is i think around 30-40% swords, rest ballista.
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