Why did the scutum have a horizontal grip?

[Marius_Ursus]

Two reasons.

1.) The horizontal grip is far more comfortable on the wrist after a long march. It is easier to hold for a long battle without tiring.

2.) The horizontal grip allows you to rest the top edge on your shoulder which helps distribute the weight and also allows you to push back with your body.

Travis

I've come to the same conclusion. It makes the most practical military-application sense.