Interior Decorations.—Leonardo had formed a new and close friendship with Luca Pacioli of Borgo San Sepolcro, the great mathematician, whose Summa de aritmetica, geometrica, etc., he had eagerly bought at Pavia on its first appearance, and who arrived at the court of Milan about the moment of the com pletion of the "Cenacolo." The two begin working together on the materials for Pacioli's next book, De diving proportione. But he was soon called away by Ludovico to a different under taking, the completion of the interior decorations, already begun by another hand and interrupted, of certain chambers of the Castello called the Saletta Negra and the Sala Grande dell' Asse, or Sala della Torre. When, in the last decade of the 19th century, works of thorough architectural investigation and repair were undertaken in that building under the superintendence of Senatore Luca Beltrami, a devoted foreign student, Dr. Paul Muller Walde, obtained leave to scrape for traces of Leonardo's handi work beneath the replastered and white-washed walls and ceilings of chambers that might be identified with these. In the great Sala dell' Asse (or della Torre) abundant traces of Leonardo's own hand were found, in the shape of a decoration of intricate geometrical knot or plait work combined with natural leafage; the abstract puzzle-pattern, of a kind in which Leonardo took peculiar pleasure, intermingling in cunning play and contrast with a pattern of living boughs and leaves exquisitely drawn in free and vital growth. Sufficient portions of this design were found in good preservation to enable the whole to be accurately restored. Leonardo was rewarded in 1498 (ready money being with difficulty forthcoming and his salary being long in arrears) by the gift of a suburban garden outside the Porta Vercelli.
Work as Military Engineer.—He was then called away on duty as chief military engineer (ingegnere camerale) with the special charge of inspecting and maintaining all the canals and waterways of the duchy. Dangers were accumulating upon Ludo vico and the state of Milan. France had become Ludovico's enemy; and Louis XII., the pope and Venice had formed a league to divide his principality among them. Ludovico travelled to Innsbruck, the better to push his interests (Sept. In his absence Louis XII. invaded the Milanese, and the officers left in charge of the city surrendered it without striking a blow. The French lieutenant in Milan, Gian Giacomo Trivulzio, the embittered enemy of Ludovico, began exercising a vindictive tyranny over the city which had so long accepted the sway of the usurper. Great artists were usually exempt from the consequences of political revolutions, and Trivulzio, now or later, commissioned Leonardo to design an equestrian monument to himself. Leonardo, having remained unmolested at Milan for two months under the new regime, but knowing that Ludovico was preparing a great stroke for the re-establishment of his power, and that fresh convulsions must ensue, thought it best to provide for his own security. In December he left Milan with his friend Luca Pacioli, having first sent some of his modest savings to Florence for investment. His intention was to watch events. They took a turn which made him a stranger to Milan for the next seven years.
Ludovico, at the head of an army of Swiss mercenaries, re turned victoriously in Feb. i soo, and was welcomed by a popu lation disgusted with the oppression of the invaders. But in April he was once more overthrown by the French in a battle fought at Novara. Ludovico was taken prisoner and carried to France; the city, which had been strictly spared on the first entry of Louis XII., was entered and sacked; and the model of Leonardo's great statue made a butt (as eye witnesses tell) for Gascon arch ers. Two years later we find the duke Ercole of Ferrara begging the French king's lieutenant in Milan to let him have the model, injured as it was, for the adornment of his own city; but nothing came of the petition, and within a short time it seems to have been totally broken up.
Work at Milan (1483-99).—Thus, of Leonardo's sixteen years' work at Milan (1483-99) the results actually remaining are as follows: "Virgin of the Rocks."—The Louvre "Virgin of the Rocks" possibly, i.e., as to its execution; the conception and style are essentially Florentine, carried out by Leonardo to a point of intense and almost glittering finish, of quintessential, almost over strained, refinement in design and expression, and invested with a new element of romance by the landscape in which the scene is set—a strange watered country of basaltic caves and arches, with the lights and shadows striking sharply and yet mysteriously among rocks, some upright, some jutting, some pendent, all tufted here and there with exquisite growths of shrub and flower. The National Gallery "Virgin of the Rocks" certainly, with help from Ambrogio de Predis; in this the Florentine character of the original is modified by an admixture of Milanese elements, the tendency to harshness and over-elaboration of detail softened, the strained action of the angel's pointing hand altogether dropped, while in many places pupils' work seems recognizable beside that of the master. The "Last Supper" of Sta. Maria delle Grazie, his masterpiece ; as to its history and present condition enough has been said. The decorations of the ceiling of the Sala della Torre in the Castello. Other paintings done by him at Milan are men tioned, and attempts have been made to identify them with works still existing. He is known to have painted portraits of two of the king's mistresses, Cecilia Gallerani and Lucrezia Crivelli. Cecilia Gallerani used to be identified as a lady with ringlets and a lute, depicted in a portrait at Milan, now rightly assigned to Bartol ommeo Veneto. More lately she has by some been conjecturally recognized in a doubtful, though Leonardesque, portrait of a lady with a weasel in the Czartoryski collection at Cracow. Lucrezia Crivelli has, with no better reason, been identified with the famous "Belle Ferronniere" (a mere misnomer, caught from the true name of another portrait which used to hang near it) at the Louvre; this last is fine work of one of his pupils. Mention is made of a "Nativity" painted for and sent to the emperor Maximilian, and also apparently of some picture painted for Matthias Corvinus, king of Hungary; both are lost or at least unidentified.