That letter which Leonardo wrote to Lodovico Sforza is still extant, and it throws so much light upon his genius and his selfknowledge that it is worth quoting almost entire:
Having, most illustrious lord, seen and considered the experiments of all those who repute themselves masters and inventors of warlike instruments, and having observed that their said instruments are nowise different from those in common use. I will attempt, without disparaging any one else, to explain myself to your Excellency; opening for this purpose my secrets. . . .
1. I have a way of making bridges, very light and adapted to be carried very easily, by which to pursue or escape from an enemy; and others more secure, and indestructible by fire and battle, easy and convenient to set in position and to re- move. And means for burning and destroying those of the enemy.
2. In investing a place, I know how to remove water from fosses, and to make various scaling-ladders, and other instruments pertinent to such an expedition.
3. Item, if. on account of the bank or strength of place and site, in the siege of a city cannon cannot be used. I have means of undermining every fortress, pro- vided it be not founded on stone.
4. I can make cannon easy and convenient to transport, by which burning stuff can be discharged, whose smoke will cause great fear to the enemy, to his seri- ous harm and confusion.
5. Item, lean make mines and narrow and winding ways to reach without noise a given [point]; and, if need be, I can make them pass under trenches or a river.
6. Item. lean make covered carts, secure and indestructible, which, with their artillery, entering among the enemy, will break the strongest body of men ; and behind these carts infantry can follow unwounded and without any hindrance.
7. Item, if necessary, I will make cannon, mortars, and fire-arms of most useful and beautiful forms, different from those in common use.
8. When cannon are impracticable, I will devise catapults, mangonels, mor- tars (traburiii), and other instruments of wonderful efficacy and novelty ; and, in short, according to the variety of needs. I will invent divers and many engines of offence
9. And if by sea, I have a lot of instruments most suitable for attack and defence ; and vessels that will resist the fire of the heaviest cannon; and powders and fire-stuffs
10. In time of peace, I believe I can give good satisfaction—in comparison with any other—in architecture, in constructing edifices, both public and private, and in conducting water from one place to another.
“Item, I can do in sculpture of marble, bronze, or clay, likewise in painting, equally as well as any uther, be he who he may. Further, the work might be executed on the bronze horse, which will be the immortal glory and eternal honor of the happy memory of your father, and of the illustrious House of Sforza. And if to anybody any of the above-mentioned things seem impossible and unachievable, I offer myself most ready to make trial of them in your park, or in whatever place shall please your Excellency, to whom in all humility I commend myself.”
In this letter, written when he was only twenty-seven or twenty-eight, Leonardo magnifies his ability as an engineer and speaks but briefly of his skill as an artist—briefly, but haughtily, as that phrase “equally as well as any other, be he who he may,” bears witness.
In a little man such an inventory of talents would sound presumptuous, but Leonardo can do all that he announces. He is seeking employment from a military tyrant who needs engines for conquering his foes more than he needs paintings or statues; and therefore Leonardo insists on his own pre-eminence as an engineer. But there shall be frescoes, too, and monuments, and rare products of the arts of peace, if only Louis “the Moor” will listen to him.