Before the completion of the Eremitani frescoes, Mantegna had married Niccolosia Bellini, had profited largely by her father’s advice, and had influenced strongly her two brothers, Gentile and Giovanni. They seem to have been the first eager pupils of the man who was soon to be the artistic schoolmaster for all Northern Italy. Two years after his marriage, in 1455, Mantegna liberated himself from legal bondage to Squarcione, and soon after began the masterpiece of his developed Renaissance style, the altar-back for San Zeno Maggiore at Verona, Figure 218. It was finished in 1459, the artist being twenty-eight years old. It is a little over-rich, finished throughout like a miniature, and very stately. In arrangement it obeys the artist’s new law of illusion. The base of the picture is precisely at the level of the eye, so no floor is seen. The carved classical frame is regarded as the front of an actual pavillion which is continued in paint. Without the frame, the architectural perspective of the picture would not explain itself, and if the picture were set higher or lower all the perspective relations would be wrong. At Siena, a century and more earlier, the Lorenzetti had devised this motive of an open box of which the frame is the plastic front. Mantegna made this sort of illusionism standard for Venice and all Northern Italy. Its value is open to question, but I believe that the monumental altar-pieces of Mantegna and Giovanni Bellini gain something in gravity and stability from this careful adjustment of the perspective to the actual position of the spectator. At any rate it was the rigid logic and probity of Mantegna that gave to Venetian art precisely the tonic stimulus it needed.