Having, my most illustrious Lord, now seen and sufficiently considered the trials of all those who count themselves masters and makers of instruments of war, and finding that the invention and working of the said instruments are in no way different from those in common use, I shall endeavour, without disparaging anyone else, to make myself understood by Your Excellency, disclosing to you my secrets, and thereafter offering, at your pleasure and in due season, to carry into effect all those things which are in part briefly noted below (and yet many more, according to the occurrence of the various cases, and so forth).

I have plans for bridges, very light and strong and fit to be carried most easily, with which to pursue and, on occasion, to flee the enemy; and others, secure and proof against fire and battle, easy and convenient to raise and to set down; and ways to burn and destroy those of the enemy.

In the siege of a place I know how to draw off the water of the moats and to make countless bridges, mantlets, scaling-ladders and other instruments pertaining to such an expedition.

3. Likewise, if by the height of an embankment or by the strength of the position and site a place under siege could not be reduced by the office of bombards, I have ways to ruin every fortress or other stronghold, unless it be founded upon rock, and so forth.

4. I have besides ways of bombards most convenient and easy to carry, and with them to hurl small stones almost after the manner of a hailstorm; and with the smoke of these giving great terror to the enemy, to his grave hurt and confusion, and so forth.

9. And should it happen to be at sea, I have ways of many instruments most apt to attack and to defend, and vessels that will resist the fire of the very heaviest bombard, and powder and smoke.

Also I have ways, by secret and winding mines and passages, made without any noise, to reach a given and appointed place, even if it were needful to pass beneath moats or some river.

Also I will make covered chariots, secure and unassailable, which, entering among the enemy with their artillery, no multitude of men-at-arms is so great but they would break through it; and behind these the infantry could follow in numbers, unhurt and without any hindrance.

Also, should the need arise, I will make bombards, mortars and light ordnance of very beautiful and useful forms, out of the common use.

Where the working of bombards should fail, I will contrive catapults, mangonels, trebuchets and other instruments of marvellous efficacy and out of the ordinary; and in short, according to the variety of the cases, I will contrive various and infinite means of attack and defence.

10. In time of peace I believe I can give satisfaction fully equal to any other in architecture, in the composition of buildings both public and private, and in conducting water from one place to another. Likewise I will execute sculpture in marble, in bronze and in terracotta; and in painting whatever may be done, to bear comparison with any other, be he who he may.

Moreover, the bronze horse could be undertaken, which shall be to the immortal glory and eternal honour of the happy memory of the Lord your father and of the illustrious house of Sforza. And if any of the aforesaid things should seem to anyone impossible or unfeasible, I offer myself most ready to make trial of them in your park, or in whatever place shall please Your Excellency, to whom I commend myself as humbly as I possibly can, and so forth.