Considering the Roman Empire basis of the Auran Empire why isn't there a proficiency which expands the benifits of using a shield? Afterall the greek city states and the roman empire both used large shields, often in place of armoring the entire body. Basically why isn't there a 300 inspired fighter build who wears practically no armor but has a huge shield, grieves, a short sword, and a spear? I mean Spear and big whopping sheild are sort of mankinds go-to armaments. 

There is a proficiency: Fighting Style - Weapon and Shield.

But really, if you want shields to matter, you have to step away from the high medieval milieu ACKS inherits by way of B/X, whereby armour is king and shields are optional accessories. I did this in my historical hack, Tyche's Favourites.

More specifically, after rejigging armour, I gave shields a more detailed and extensive treatment. Instead of all shields just being a flat +1AC regardless, there are five classes of "shield". I use scare quotes, because a cloak wrapped around the forearm in an emergency is classed as a shield too. Though only against light melee weapons. There's also a distinction between melee and ranged protection; generally shields offer much more protection against missiles, due to coverage.

In actual play this worked out very well; there was a surprise combat where intruders raided the PCs' employer's home in the night, they were all out of armour and indeed naked for the most part. Rather than taking valuable minutes armouring up, they simply scooped up shields and weapons and leapt into the fray.

I think you'd simulate the movie's 300 Spartans in ACKS as fighter-types built with Swashbuckling or Graceful Fighting (+1 AC in light armor, +2 at 7th level, +3 at 13th level) and Weapon & Shield Proficiency (+1 AC with shield).

Assuming that their greaves and helms count as just AC 1, that would give a total AC of 1 (armor) + 1 (swashbuckling) + 1 (shield) + 1 (shield proficiency) = 4, the equivalent of a chainmail byrnie. 

I think one could also imagine a "heavy shield" that offers an additional +1 to AC at a cost of -1 to hit, due to its cumbersome size, or similar variations. Kiero did a splendid job of working all sorts of variations out.



There is also a decent OSR houserule called Shields Shall be Splintered that allows one to sacrifice their shield to negate a successful attack.

although Alex specifically debunked that one: it creates a perverse incentive to carry around a large collection of shields to replace as the dungeon crawl progresses.

Didn't think of that, but that would totally work. The setting I'm working up is early middle ages so huge shields are rare, but there could be a few societies (humanoids, and a handfull of human holdovers)  that still rock the giant shield. Although I'd still need to workup cover rules for sorcerers/archers/crossbowmen hiding behind pavis's. 

I have done a lot of sparring, reading, and play testing d&d style games. While I really think "great" weapons trump shields in duels I think shield using troops have two advantages over other weapons. 1) they can hold a line better than anything but pikes  2) they are great vs  missile weapons.  The first is hard to simulate but I did once try with minatures. It worked for awhile but the added complexity was easy to forget. Basically you can't attack without a shield if you don't move one square.  The second was easy. If not engaged in males a character could take cover behind their shield.    



Pikemen used shields, historically. In the Macedonian phalanx, a pikeman strapped a small shield to his shoulder/upper arm. It was mostly for added protection against missiles, but also random thrusts of enemy pikes.

If it's on his shoulder/upper arm, is it any different than any other armor (as opposed to shield on forearm that can be repositioned)?

Depending where it's fixed, it might be slightly mobile - I can imagine if on the upper arm you could move it up to protect your neck/face. But as with everything in the phalanx, most of it is designed with being static in mind.


Though unlike armour, it isn't relying on the contours of the body, since it projects out around a point. Given the success of the system in that configuration, I have to assume the ancients knew what they were doing.

Oh, agreed! I wasn't trying to question it in that way, more just asking if there was any reason to treat it as anything other than very light armor like hide or padded (i.e., +1 AC) in ACKS, while disallowing it to benefit from weapon and shield style fighting.

Pikemen of the Classical period did, 15th+ century pike, no. 

That's probably a reasonable thing to do - more important in Battles where it would give a bonus against missiles for the unit as a whole. Everything about the pike phalanx is done with regards to the collective effort, rather than the individual.

Hellenistic period (a couple of centuries after the high point of the Classical), but yes, that's true.