Hybrid Phalanx Theory

[WriterNotViking]

That could work, but it would probably have disadvantages. Several I can think of include:
- Space requirements. Polybius states that a swordsman needs twice as much width (4 cubits) as a pikeman (2 cubits) to fight effectively. You can pack swordsmen into 2 cubits per man without hambering them too badly, but what if the pikemen want to close up to 'locked shields' with 1 cubit per file?

I appreciate your thoughts on the idea. This is certainly an issue to consider. Perhaps large shields would limit the reduction of space necessary to achieve the effect of locked shields?

- Reduced reach. The front rank of another pike phalanx would be able to strike the front rank of the composite phalanx before the second rank of the composite phalanx could strike back.

A very real concern that had not yet occurred to me.

- Complexity. Now you have to train two types of heavy infantry (and supply replacements as men die, retire, sicken, or get promoted). And if you want to detach your swordsmen on a seperate mission, you're breaking up fighting uints. Training your pikemen to defend themselves with swords at close range would be easier.

I failed to give additional details on which aspects of the army I had already developed. It consists of professional soldiers, trained to fulfill one of several specific roles. The question I posted is in regards to the heavy infantry of the army, who are trained to fight with both the pike and the sword. Your final conclusion here is one that sounds most effective to me.

- A spear phalanx would end up with a thinner, shorter hedge of spikes to keep cavalry off.

Another point I had not considered.

Complicated mixed formations did get used, so I don't see anything wrong with one in a fantasy setting, but they don't seem to have been much more effecive than traditional ones. I think Machiavelli suggested backing a pike formation with sword-and-buckler men who would move forward after the initial clash, and Arrian and Xenophon suggested backing a shallow phalanx with archers and javelin men to throw over the heads of the front ranks.

The historical references here are very interesting. My own Google searches had found little of value, certainly no sources of any kind that debate the potential of mixing other unit types into the phalanx. While reading through older topics on this forum, I found a thread that covered a different application of the concept, but did not yield the answers I sought. The fact that contemporary writers felt the idea had merit, in addition to the insightful replies you have given me, reassures me that there is sufficient grounds to believe a fictional military organisation could, in principal, adopt such a tactic.