1.Dux (commanding offcer or general). After his first impotrant victory he had a right to the 
     title imperator (commander-in    chief). Caesar used the title imperator from the time he
     defeted the Helvetians    in 58 B.C. untill his death.

   2.Legati (staff officers). The legatus was next in rank to the dux, equavalent to the lieutent-
     general in the United States Army. Legati were men of senatorial rank appointed by the Romans
     Senate.
  
   3.Quaestores (quartermasters). They were also of senatorial rank, elected for one year by the
     Roman people. The quaestors handled pay, military equiptment, and the food supply. Sometimes 
     a quaestor commanded a legion in battle. 

   4.Tribuni militun (military tribunes). There were the lowest-ranking commissioned officers, 
     and numbered six to a legion. They were men of good families, without previous military 
     experience, who gained appointment for their political or personal reasons. Their duties
     incluede: command of a legion in camp or on the march, supervision of dirll exercises, and 
     muster abs discharge of soldiers.

   5.Centuriones (centurions or captains). They were noncommissioned officers of plebeian orgin,
     equauivalent in rank to sergeants in the United States Army. Unlike military tribunes, 
     centurions were experienced soliders who rose from the ranks by virtue of courage and
     ability on the battlefield. There was one centurion in each century, and sixty in a legion.

   6. Praefecti (prefects). They were in command of the auxiliaries of cavalry.

   7. Decuriones (decurions). They were in command of the decuriae.