There are four other bronze reliefs, the Symbols of the Evangelists.  Donatello has contrived to invest these somewhat awkward themes with alternate drama and poetry.  The emblems of Ezekiel’s vision were too intricate for Western art, and long before the fifteenth century they had been reduced to the simple forms of the lion, ox, eagle and angel, with no attribute except wings.  All four reliefs are rectangular, about eighteen inches square.  The ox is, of course, the least inspiring, and here as elsewhere is treated in a dry perfunctory manner.  The oxen on the facade of Laon Cathedral offered some scope to the sculptor, being life-sized; but in a small relief the subject was not attractive.  The lion is more vigorously treated.  As a work of natural history he is better than the Marzocco, and he has a certain heraldic extravagance as well.  The limbs have tension, the muscles are made of steel, and there is strength and watchfulness, attributes which led the early architects to rest the pilasters of the pulpit and portal upon lions’ backs.  But the eagle of St. John is superb, even grander than the famous classical marble of the same subject.[199] It has the broad expanse of wings, vibrating as though the bird were about to take flight:  the long lithe body with its soft pectoral feathers, the striking claws, and the flattened head with cruel gleaming eye, all combine to give a terribilita which is, perhaps, unsurpassed in all the countless versions of the symbol.  But the drama of the eagle is eclipsed by the quiet unostentatious poetry of the angel of St. Matthew.  We see a girl of intense grace and refinement, winged as an angel and looking modestly downwards to the open gospel in her hands.  Delicacy is the keynote pervading every detail of the relief:  in her hands, arms and throat, in the soft curves of the young frame, and in the drapery itself, which suggests all that is dainty and pure—­everywhere, in fact, we find charm and tenderness, rare even in a man like Ghiberti, almost unique in Donatello.

[Footnote 199:  The Walpole Eagle from the Tiber, belonging to the Earl of Wemyss.]

* * * * *

[Sidenote:  The Choir of Angels.]

In the original contract with Donatello, ten angels were commissioned, and were exhibited on the provisional wooden altar (13, vi. ’48).  It appears, however, that they were insufficient, and two more panels were ordered.  These may possibly be the reliefs in each of which a couple of angels are represented singing, certainly the most successful of all.  There is a palpable inequality in the remainder.  They not only show differences of treatment in the details of drapery, chiselling and general decoration, but there is a substantial lack of harmony in their broad conception.  It is impossible to believe that the two angels leaning inwards against the edge of the relief (the fourth respectively from either end of the altar) could have been modelled by Donatello.