Quote Originally Posted by Philipvs Vallindervs Calicvla
Thing about the Romans though is that their "professional" army were really more cutthrout mercs or monarchial King's retainers, depending on which way you look at it.
The Praetorians were the "cut-throat mercs" for much of their history. It would not be fair to pigeonhole the majority of the Roman legions as being inherently disloyal. All military forces throughout history are really no different in that respect. There were civil wars and rebellions in the Seleucid and Ptolemaic kingdoms as well.