@bobbin, i do not know Paullus Scipio, i offer my apologies if anyone felt offended, still...where is the historical evidence of oscan thureos or thureos in the principes army? other then a resemblence of shape which can also be attribuited to a certain context. Can't this be just a convergent evolution unrelated with the influence of the celtic Hallstad and La Tene culture by the Villanova as Moros said?
I also never spoke with MeinPanzer but he does not present any sources of any sort of a principes thureos or a oscan thureos. Sitalkes makes no point in that disscusion other that it was used by the illyrians so it doesnt help your claim.
Having two kinds of shields, one created by the celts one by the romans,the later according to Polybios and Titus Livius have taken the pattern from the oscans, doesnt make the principes use a thureos so i still dont see any sources, literary or archeological about a thureos in the principes panoply or oscan one, just a resemblance and a link with a 600 years prior of the game start "extinct" culture.
So where are the sources?

If u want u can foward this debate to Paullus so he can answer here or pm me about it.