It might have been expected that the glory of this achievement would have brought the troubles of Artabanus to a close; and if they did not cause the pretender who still disputed his possession of the throne to submit, would at any rate have put an end to any disaffection on the part of the subject nations that the previous ill-success of Parthia in her Roman wars might have provoked. But in the histories of nations and empires we constantly find that noble and gallant efforts to retrieve disaster and prevent the ruin consequent upon it come too late. When matters have gathered to a head, when steps that commit important persons have been taken, when classes or races have been encouraged to cherish hopes, when plans have been formed and advanced to a certain point, the course of action that has been contemplated and arranged for cannot suddenly be given up. The cause of discontent is removed, but the effects remain. Affections have been alienated, and the alienation still continues. A certain additional resentment is even felt at the tardy repentance, or revival, which seems to cheat the discontented of that general sympathy whereof without it they would have been secure. In default of their original grievance, it is easy for them to discover minor ones, to exaggerate these into importance, and to find in them a sufficient reason for persistence in the intended course. Hence revolutions often take place just when the necessity for them seems to be past, and kingdoms perish at a time when they have begun to show themselves deserving of a longer term of life.