In war, standing in formations, yes. After a certain point in time those became dominant. The situation we players are in is usually not on a battlefield though.
There's little point debating it because the D&D concept of an "adventurer" is entirely ahistorical in and of itself, the closest analogue would be a small time bandit. The medieval and ancient worlds did have a notion of the "adventurer", but it might've referred to the likes of Alexander the Great, Crusader princes or Norman mercenary lords stealing parts of Italy for themselves - i.e. warlords with their own personal armies plundering far-off lands and establishing fiefdoms for themselves, not a couple of jerkoffs who go spelunking in full plate. The seminal image of the solitary itinerant knight, roaming the realm and doing chivalrous deeds, is merely a romanticisation of the freelancer who'd join in such "adventuring" armies.
The reason I bring it up is because much of the weapons and armour we see in D&D is inspired by medieval warfare equipment, the sort designed for fighting large unit engagements, and would be entirely unsuitable for the aforementioned couple of jerkoffs. Medieval armies marched with a baggage train and an extensive support contingent of non-combatants, they weren't post-Marian Roman legions. As much as I love full plate armour, it was incredibly expensive, required extensive maintenance, help and time to equip, it was a burden to carry etc., and the fantasy of the small-time D&D adventurer looting ancient tombs while decked in a Maximilian harness is just that - a fantasy.
I feel the dark urge rising.
Don't do it, The Dark Urge is still an origin character, you're just playing into
Swen's hands! Do the right thing, murder all the companions and roll your own custom henchmen - no backtalk, no "funny", just point and cli... Oh wait, poor choice of words.