Thureos, Scutum, Shield
I have seen many historians and reenactment groups who seem to point towards the fact that the large oval body shield of Italic and celtic types were small. Rubbish! There are many pieces of evidence that the scutum or thureos were large enough to cover from the shoulder to either half the shin or even ankle. Archaeological evidence from Britain to Egypt proves this. In Asia Minor, aka Turkey today, there are stelae that are from the Bithynian people that lived there, and prior to the Galatian migration, they had been using hellenistic round aspis. The Galatians or Gauls meanwhile, were using the thureos or scutum, a distinctive large oval body shield. When the Galatians did settle, their military influence swept the hellenistic world and the successor peoples began using and recording their use of it.
The picture abouve is known as 'Stele C' from the Grave stele of Diliporis, found in Kutluca, 1st half of 2nd century BC. It clearly shows in accurate proportions the size of a thureos adopted by the Bithynians during the Galatian period.
Here is a flickr with more Bithynian stele:
http://www.flickr.com/photos/thracian/sets/72157625430580348/