When did the Skutatoi come around?

[Poftim]

I was reading some info on the Byzantine's and saw that their infantry was called Skutatoi. Wikipedia has this to say:

Skutatoi

The bulk of the byzantine infantry were the skutatoi, named from the word skutos, for their large oval shield. These men were professional soldiers paid by the state. The skutatoi evolved from the Comitatenses of the later empire and were equipped much as the same as these legionaries. Their armor and weapons included:

* kresamata: A skirt hanging below a soldier's cuirass to protect his legs.
* κlibanion (κλιβάνιον): the characteristic Byzantine lamellar cuirass, usually sleeveless. In addition, pteruges (leather hanging strips) were worn to protect shoulders and hips.
* zaba (ζάβα) or lorikion (λωρίκιον): mail hauberks, usually reserved for the heavy cavalry cataphracts.
* bambakion (βαμβάκιον): A padded leather or cotton under-garment, worn under the cuirass.
* epilorikion (επιλωρίκιον): A padded leather or cotton over-garment, worn over the cuirass.
* spathion (σπαθίον): The typical Roman spatha, a longsword (about 90 cm), double-edged and very heavy.
* paramerion (παραμέριον): a one-edged scimitar-like sword, girded at the waist.
* kontarion (κοντάριον): a long spear (about 2 to 3 m), the kontarion was used by the first ranks of each chiliarchia (battalion) in order to fend off enemy cavalry.
* Helmet: the helmet varied by region and time but was generally a simple, conical-shaped piece of steel, often with extra neckguard.
* skutos (σκούτος): a large and oval (later kite-shaped) shield made of wood, covered by leather and reinforced with steel. Each unit had different shield decoration.

Unarmoured light infantrymen, often armed with javelins, were known as in classical times as peltastoi.