Maille During the Time of Darius I

[Paullus Scipio]

In this respect, the design is deceptively simple, though. The tube-and-yoke actually has a fairly unique design if you take into consideration its characteristics. They are:

1) A tube body.

2) Two loose, roughly rectangular shoulder yokes which are tied down at the front.

3) A rectangular neckguard.

4) Pteruges.

5) A separate backboard which is attached to 1) and from which comes 2) and 3).

Of course some of these elements are not always present (such as 5, which sometimes is either not shown clearly on representations or was left out) or are not present in the same qualities or quantities; but if you accept that most of the time they do, and if you take these aspects together, you realize that it is pretty hard to chance upon this particular design......
.......And on top of that, organic armour of the Greek style (whether linen or leather) is not found. So the tube-and-yoke is actually pretty complex and hard to chance upon, and I think it's pretty safe to assume a single origin for it.

One would be tempted to add another criteria.." made of organic material, often leather and sometimes quilted linen, and often re-inforced entirely or to a lesser degree with metal scales or plates" ....but for that all-iron example from the 'Philip Tomb'.
And of course not all are a separate 'Tube' and 'Yoke' - some in Greek art seem to be cut in a single piece with no 'separate backboard', but instead the shoulder pieces and neck-guard are simply an extension of the back of the 'Tube'.......