Having, most illustrious lord, seen and considered the experiments of all those who pose 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 appointment 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 fire or assault, yet are easily removed and placed in position; and I can also burn and destroy those of the enemy.
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 his 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. When it is impossible to use cannon I can supply in their stead catapults, mangonels, trabocchi, and other instruments of admirable efficiency not in general use—I short, as the occasion requires I can supply infinite means of attack and defense.
9. And if the fight should take place upon the sea I can construct many engines most suitable either for attack or defense and ships which can resist the fire of the heaviest cannon, and powders or weapons.
10. In time of peace, I believe that I can give you as complete satisfaction as anyone 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 anyone 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.
Leonardo Da Vinci