Each of these walls has a doorway at one end, and the way in which these openings are dissimulated and utilized is most ingenious, particularly in the “Disputa,” where the bits of parapet which play an important part at either side of the composition, one pierced, the other solid, were suggested solely by the presence of this door.  In the end walls the openings, large windows much higher than the doors, become of such importance that the whole nature of the problem is changed.  It is the pierced lunette that is to be dealt with, and Raphael has dealt with it in two entirely different ways.  One wall is symmetrical, the window in the middle, and on that wall he painted the “Parnassus” (Pl. 15), Apollo and the Muses in the centre with groups of poets a little lower on either side and other groups filling the spaces to right and left of the window head.  At first sight the design seems less symmetrical and formal than the others, with a lyrical freedom befitting the subject, but in reality it is no less perfect in its ponderation.  The group of trees above Apollo and the reclining figures either side of him accent the centrality of his position.  From this point the line of heads rises in either direction to the figures of Homer and of the Muse whose back is turned to the spectator, and the perpendicularity of these two figures carries upward into the arch the vertical lines of the window.  From this point the lateral masses of foliage take up the drooping curve and unite it to the arch, and this curve is strongly reinforced by the building up toward either side of the foreground groups and by the disposition of the arms of Sappho and of the poets immediately behind her, while, to disguise its formality, it is contradicted by the long line of Sappho’s body, which echoes that of the bearded poet immediately to the right of the window and gives a sweep to the left to the whole lower part of the composition.  It is the immediate and absolute solution of the problem, and so small a thing as the scarf of the back-turned Muse plays its necessary part in it, balancing, as it does, the arm of the Muse who stands highest on the left and establishing one of a number of subsidiary garlands that play through and bind together the wonderful design.

[Illustration:  Plate 15.—­Raphael.  “Parnassus.”  In the Vatican.]

The window in the opposite wall is to one side of the middle, and here Raphael meets the new problem with a new solution.  He places a separate picture in each of the unequal rectangles, carries a simulated cornice across at the level of the window head, and paints, in the segmental lunette thus left, the so-called “Jurisprudence” (Pl. 16), which seems to many decorators the most perfect piece of decorative design that even Raphael ever created—­the most perfect piece of design, therefore, in the world.  Its subtlety of spacing, its exquisiteness of line, its monumental simplicity, rippled through with a melody of falling curves from end to end, are beyond description—­the