The artist himself was more interested in the torso than the head; some artists came to be regarded as specialists in their own lines; Calcosthenes for instance, who made athletes, and Apollodorus, who made philosophers.  Donatello made several portrait-busts, and two or three others, such as the head of St. Laurence, and the so-called St. Cecilia in London, which are portraits in all essentials.  These two are idealised heads, both made late in life, judging from a certain sketchiness, in no way detracting from their sterling qualities, but indicative of Donatello’s fluency as an oldish man.  Both are in terra-cotta.  The St. Laurence is placed on the top of one of the great chests in the Sacristy of San Lorenzo, too high above the eye-level.[164] It has no connection with the decorative work carried out there by the master, and it is difficult to see how it could have been meant to fit in with the altar.  However, the authorship of Donatello is beyond question.  St. Laurence is almost a boy, wearing his deacon’s vestments.  His head is raised up as if he had just heard something and were about to reply.  The eager and inquiring look is most happily shown.  The sentiment of this bust is quite out of the common; it has an engaging expression which is rare in the sculpture of all ages, differing from what is called animation or vivacity.  These also may be found in the St. Laurence, where the exact but indescribable movement of the face as he is about to speak is rendered with immense skill.  The bust, though modelled with a free hand, is not carelessly executed; everything is in concord, and the treatment of the clay shows exceptional dexterity, more so, at any rate, than is the case in the St. Cecilia.[165] The name given to this bust is traditional, there being no symbol to connect it with her; but it suggests at least that the work was not meant purely as a portrait.  In technique and conception it is not quite equal to the St. Laurence, but it is none the less a work of rare merit, and being Donatello’s only clay portrait in this country has a special value to us.  The Saint looks downwards, pensive, quiet and modest, the embodiment of tranquillity and calm.  There is no movement or effort about her, neither does the work show any effort on the part of the sculptor.  It is equable in a very marked degree; the smooth regular features are simple and well defined, and the hair, brushed back from the forehead, has a softness which could scarcely be obtained in marble.  The bust known as Louis III. of Gonzaga is interesting in another way:  it is bronze and has been left in an unfinished state.  Two versions of it exist—­one in Berlin, the other in Paris, belonging to Madame Andre, the latter being perhaps the less ugly of the two.  It used to be known as Alfonso of Naples, on the assumption that Donatello must surely have made a bust of that prince.  This theory, however, had to be abandoned, and it is now held to be a portrait of the Gonzaga as being a closer resemblance to him