Sabba da Castiglione (1485?-1554), in his " Ricordi," says that Leonardo was at work on the Sforza statue for sixteen years continuously.1 This argues his presence in Milan in 1483, as he had quitted the city by the close of the year 1499.

The date tallies with the statement of the " Anonimo Florentine-" that Leonardo, when aged thirty, was sent by Lorenzo de' Medici to the Duke of Milan with a lute, from which it would follow that he went to Milan in 1482 or 1483.

1 "Ricordi" (1561), 115 v., "Si occupo nella forma del cavallo di Milano, ove sedici anni continui consumo."

Braun and Co. photo - The Louvre

The Milanese Court offered a greater scope for his ambition. How high that ambition soared the records of his life at Milan set forth; but it is foreshadowed in the draft of a letter1 in which Leonardo offered his services to Ludovic. The writing is from left to right, and M. Ravaisson-Mollien considers in consequence that the original connection of the letter with Leonardo is a matter of uncertainty. The handwriting in Leonardo's manuscripts is from right to left. Occasionally, however, he wrote in the usual manner. Two such instances of his signature may be cited, viz., that on No. 1640 of the Louvre drawings, The Scene of Magic, and that reproduced from the Windsor MSS. on p. 175 of Mr. Cook's "Spirals." His manuscripts were usually intended solely for his own use; but if this letter were to be read by Ludovic it would have to be written presumably in the ordinary manner, and the draft at its commencement may have bid fair to be the definite letter. But suppose it written by a pupil! The question of calligraphy is of little import. The contents are the strongest proof of its authenticity.

"Having, most illustrious lord, seen and considered the experiments of all those who pass as masters in the art of inventing instruments of war, and finding that their inventions differ in no way from those in common use, I am emboldened, without prejudice to anyone, to solicit an opportunity of acquainting your Excellency with certain of my secrets :

" 1. I can construct bridges which are very light and strong and very portable, with which to pursue and defeat the enemy; and others more solid, which resist lire or assault, yet are easily removed and placed in position; and I can also burn and destroy those of the enemy.

1 Cod. Atl., 391 r.

"2. In case of a siege I can cut off water from the trenches and make pontoons and scaling ladders and other similar contrivances.

" 3. If by reason of the elevation or the strength of its position a place cannot be bombarded, I can demolish every fortress if its foundations have not been set on stone.

"4. I can also make a kind of cannon which is light and easy of transport, with which to hurl small stones like hail, and of which the smoke causes great terror to the enemy, so that they suffer heavy loss and confusion.

" 5. I can noiselessly construct to any prescribed point subterranean passages either straight or winding, passing if necessary underneath trenches or a river.

"6. I can make armoured wagons carrying artillery which shall break through the most serried ranks of the enemy, and so open a safe passage for the infantry.

"7. If occasion should arise I can construct cannon and mortars and light ordnance in shape both ornamental and useful and different from those in common use.

"8. Where it is impossible to use cannon I can supply in their stead catapults, mangonels, trabocchi, and other instruments of admirable efficacy not in general use. In short, as occasion requires I can supply infinite means of attack and defence.

" 9. And if the fight should take place upon the sea I can construct many engines most suitable either for attack or defence, and ships which can resist the fire of the heaviest cannon, and powders or vapours.

" 10. In time of peace I believe that I can give you as complete satisfaction as any one else in the construction of buildings both public and private, and in conducting water from one place to another.

"I can further execute sculpture in marble, bronze or clay, also in painting I can do as much as any one else whoever he may be.

" Moreover I would undertake the commission of the bronze Horse, which shall endue with immortal glory and eternal honour the auspicious memory of your father and of the illustrious house of Sforza.

"And if any of the aforesaid things should seem to anyone impossible or impracticable, I offer myself as ready to make trial of them in your park or in whatever place shall please your Excellency, to whom I commend myself with all possible humility."

In so far as the evidence of Leonardo's own MSS. can avail to substantiate the claims made in this astonishing document they are found to have been literally true. Dr. Miiller-Walde,1 in the section of his work which treats of Leonardo as military engineer, has proved by quotations and sketches taken from the MSS. at Milan, Paris and Windsor that Leonardo did in fact study deeply the construction and use of each method and instrument of warfare of which the first seven clauses of the letter offer the practical application. It would be difficult to conceive who could have had a sufficiently comprehensive knowledge of Leonardo's studies to enable him to make without error the statements made in the letter, or who could have had any possible motive in doing so.

Leonardo looked to find immediate employment fot his activities as military engineer. Cursory in comparison with the preceding detail is the enumeration of his artistic activities in the final clauses-introduced by the phrase, " in time of peace," as a period in the future.

1 " L. da V. Lebenskizze, etc.," pp. 139-232.

The war clouds which are seldom absent from a usurper's political horizon loomed portentously above Ludovic's path at the outset, and never wholly lifted throughout the two decades of his power. His lavish subsidies, which impoverished Milan, his skill in pitting adversary against adversary, the grace in diplomacy of the Duchess Beatrice all availed only to delay the impending storm, which broke and swept him before it in the autumn of 1499. In the first years of his regency Venice was his greatest menace, and the reference to the possibility of combats being by sea suggests Venice as the enemy against whom arose the immediate occasion for the services which the letter offered. Hostilities broke out between the two states in 1483, but the issue was reached by diplomacy, not by arms. Ludovic preferred other methods of combat, and there is nothing to show that at this period he employed Leonardo as military engineer.