When was the Parthian late bodygourd first use, historically?

[MeinPanzer]

Our Parthian expert has been caught up in real life and so he can't answer this question. And unfortunately, I'm not a Parthian expert myself. However, with what knowledge I have I can tell you that the late bodyguard is probably 1st century AD. It's inclusion in the Battle of Carrhae could be debated quite strongly and the one defense is that we don't truly know exactly when such incredibly heavy cavalry showed up.

I would agree with the 1st c. AD being a realistic date for such cavalry. The terracotta figurine from Seleucia on the Tigris, the frescoes from Old Nisa, and the Babylonian plaque now in the British Museum (if it is from the 2nd or 1st c. BC, and not just a late example of such armour) all show the same kind of panoply in use in the last centuries two BC: simple, pointed or bowl-like non-Spangenhelm helmet; scale cuirass; and laminated armour for the limbs. In other words, the armour of the Parthian Cataphracts and Parthian Noble Cataphracts.