The salutation was the usual preliminary to a triumph—the solemn procession of the general through the city to the Capitol at the head of his victorious army. As the title _imperator_ could be conferred only on a commander-in-chief, and was inconsistent with delegated authority, the triumph was necessarily confined to the magistrates with the capacity for supreme command—the dictator, consul and praetor,[639] and to the one of these who at the moment of victory was in highest authority. Thus the dictator usually excluded the consul,[640] the consul the praetor; and when two consuls were in command, the right resided with the one who had the _imperium_ and the _auspicia_ on the day of the victory.[641] The same rule held when the honour was granted to pro-magistrates; here too independent command was the necessary condition of a triumph. Other qualifications were fixed by custom. The return of the victorious army was originally necessary—a rule which rendered the most deserving general, who had handed over his forces to a successor, incapable of triumphing,[642] and which, with the growth of standing armies, had to be abandoned for the rule that the province must be reduced to a state of peace (_provincia pacata_).[643] The war must be a _justum bellum_, not the mere crushing a revolt of citizens or slaves;[644] and finally, the custom was fixed that it must be a war, the magnitude of which was attested by the fall of 5000 foes.[645] The right to triumph was one entirely at the discretion of the general; and as long as he chose the Alban Mount as the scene of his military pageant, no power could hinder him.[646] It was only when he wished to enter the city of Rome for the more imposing procession to the Capitol that he found difficulties in his way. The triumph implied the display of the full military _imperium_ within the city;[647] and, though instances are not lacking of magistrates who on their own responsibility successfully asserted this right,[648] the custom became fixed that permission for this display should be accorded by the state. Originally it may have been granted by the people,[649] but the permission for the exercise of the full _imperium_ for the single day soon required the consent of the Senate, all the more necessary as its control of finance enabled it to grant or refuse the money which paid the expenses of the triumph.[650] The case was otherwise with the pro-magistrate. The proconsul had only the _imperium militiae_, and none within the walls, and it was impossible, therefore, for the Senate to recognise the display of a power which did not exist. In this case a special dispensation from the laws was necessary, which could originally be granted only by the people. The Senate took the initiative by asking the tribunes to introduce a _plebiscitum_ sanctioning the arrangement.[651] The continuity of the _imperium_ from magistracy to pro-magistracy was originally a condition of the triumph. Thus it was refused to the elder