Here are significant battles where the Romans lost entire armies in significant battles. The defeat of an "entire Roman army" happened a few times in their otherwise glorious military history:
1) Battle of the Allia
2) Caudine Forks
3) Battle of Cannae
4) Arausio
5) Battle of Carrhae
6) Teutoburg Forest
7) Battle of Adrianople
8) Alaric's Attack on Rome
Yeah, the Romans had it goin' on. Unified Scotland with the Persian Gulf (briefly), eliminated Mediterranean piracy for hundreds of years, carried on trade with India...
Emperor Aurelian (Lucius Domitius Aurelianus)
Illustrated History of the Roman Empire | circa 2000 | various
Posted on 10/08/2004 9:55:02 PM EDT by SunkenCiv
http://www.freerepublic.com/focus/f-bloggers/1239592/posts
Romans in China?
Archaeology | Volume 52 Number 3, May/June 1999 | Erling Hoh
Posted on 07/18/2004 11:43:09 PM EDT by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1173944/posts
Tamil Trade
INTAMM | 1997 | Xavier S. Thani Nayagam
Posted on 09/11/2004 11:07:01 PM EDT by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1213591/posts
The Romans in Ireland
Archaeology Today | 2000? | L.A. Curchin
Posted on 07/18/2004 11:54:58 PM EDT by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1173950/posts