 Complete the following phrase:  While the historian J. B. Bury conjectured that rebellion of the British legions in 406 was aimed principally at Stilicho, the emperor Honoriuss magister militum, the ancient sources Olympiodorus of Thebes, Zosimus and Orosius generally link the rebellion to the barbarian incursions into Gaul and Italy, and specifically the Vandal and Alanic tribes that 