As we all know, the sword was used mainly as a sidearm throughout most of its history, with polearms and missile weapons being the primary casualty causers during battles and skirmishes. That being said, the sword seems to have been a fairly important sidearm, given the amount of energy that seems to have gone into designing different types for optimal performance in different situations and the extensive literature that sword-using cultures produced on how to use them.

With all that in mind, I'm curious when people think the sword enjoyed the greatest prominence as a weapon for actual combat on foot among European armies. Roman legionaries with their gladii seem to be the obvious answer, but I'm curious if anyone has any other contenders they might want to put forward (perhaps the broadswords of Scottish Jacobites?). Prominence is obviously difficult to define, so just for the sake of argument, let's define it here as a time period when, based on art, historical accounts, archaeology, etc, we think swords might have inflicted a greater proportion of casualties than they did in other eras (obviously that means a fair amount of estimating.)

Not actually battlefield, but sword and buckler deaths were wuite usual in 14th century London. ;) As far as battlefield is concerned, I would say maybe Landsknechts and their katzbalgers. Although most deaths would be from pikes, katzbalgers would be used for press and killing wounded enemies.