Caligula is here represented as young and singularly beautiful.  It is indeed an ideal Roman head, with the powerful square modelling, the crisp short hair, low forehead and regular firm features, proper to the noblest Roman type.  The head is thrown backward from the throat; and there is a something of menace or defiance or suffering in the suggestion of brusque movement given to the sinews of the neck.  This attitude, together with the tension of the forehead, and the fixed expression of pain and strain communicated by the lines of the mouth—­strong muscles of the upper lip and abruptly chiselled under lip—­in relation to the small eyes, deep set beneath their cavernous and level brows, renders the whole face a monument of spiritual anguish.  I remember that the green basalt bust of the Capitol has the same anxious forehead, the same troubled and overburdened eyes; but the agony of this fretful mouth, comparable to nothing but the mouth of Pandolfo Sigismondo Malatesta, and, like that, on the verge of breaking into the spasms of delirium, is quite peculiar to the Albertina bronze.  It is just this which the portrait of the Capitol lacks for the completion of Caligula.  The man who could be so represented in art had nothing wholly vulgar in him.  The brutality of Caracalla, the overblown sensuality of Nero, the effeminacy of Commodus or Heliogabalus, are all absent here.  This face idealises the torture of a morbid soul.  It is withal so truly beautiful that it might easily be made the poem of high suffering or noble passion.  If the bronze were plastic, I see how a great sculptor, by but few strokes, could convert it into an agonising Stephen or Sebastian.  As it is, the unimaginable touch of disease, the unrest of madness, made Caligula the genius of insatiable appetite; and his martyrdom was the torment of lust and ennui and everlasting agitation.  The accident of empire tantalised him with vain hopes of satisfying the Charybdis of his soul’s sick cravings.  From point to point he passed of empty pleasure and unsatisfying cruelty, for ever hungry; until the malady of his spirit, unrestrained by any limitations, and with the right medium for its development, became unique—­the tragic type of pathological desire.  What more than all things must have plagued a man with that face was probably the unavoidable meanness of his career.  When we study the chapters of Suetonius, we are forced to feel that, though the situation and the madness of Caligula were dramatically impressive, his crimes were trivial and, small.  In spite of the vast scale on which he worked his devilish will, his life presents a total picture of sordid vice, differing only from pot-house dissipation and schoolboy cruelty in point of size.  And this of a truth is the Nemesis of evil.  After a time, mere tyrannous caprice must become commonplace and cloying, tedious to the tyrant, and uninteresting to the student of humanity:  nor can I believe that Caligula failed to perceive this to his own infinite disgust.