Bret Devereaux

2/2 The question is, how do you read the overall formation? Traditional, triple line manipular formation in each of the 3 arrays? Or something more like a solid battle line in each array? Could frequens ordinibus signal distinction from manipular formation?

May hot take is while individual legions and ala are being used as maneuver units, probably no reason to think that they are not in their usual arrays--although the text is silent.

frequens here seems to just mean "full strength in respect to their maniples"....especially when read with recens miles...I am not sure it necessarily refers to any sort of tactical deployments.

Tended to be my thought as well: that it's part of the contrast with the state of the extraordinarii more than a statement about the formation itself. But the triple array was curious enough I had to ask.

Although having a strong forward position ahead of the main legions is something that you see in the 2nd century. Samnites and Paeligni at Pydna, and several thousand forward at Corinth in 146, probably, although I don't think explicitly extraordinarii

In this case they've been battered in the main battle line and might route at the next assault, and so not likely to be either fresh or in dense, good order.

Polybius says the extraordinarii marched in the van, but as a first line in pitched battle is a bit unusual, isn't it? At Pydna the line was lengthy and contact occurred first in their sector; I'm not sure about Corinth.

Yeah, Pydna is weird enough that we really can't say whether the mule/horse just escaped in that part of the line, or if there was some forward screen. At Corinth the screen was 12 stades forward of the main Roman army, so clearly a forward position.