The annihilation of 3 legions at Teutoburger Wald in 9 A.D. made this German river the limit of Roman expansion
[DOC] [TLE] 4.1 - Society for Classical Studies [PAR] A.D. 9, three Roman legions made their way ... large force of German tribesmen 
hidden among the trees ... the Battle of the Teutoburger Wald or the Battle of .... 
the Weser River.