As this letter makes clear, Leonardo was fully aware that to attract a powerful patron, one had to understand the potential patron’s needs and priorities. At the time this letter was written, Milan was on the brink of full-scale war with Venice, and all the duke’s energies were focused on that prospect. With this in mind, Leonardo presented himself, first and foremost, as a military engineer. As you read the letter, consider what tactics Leonardo employed to gain the duke’s interest and favor. How did the letter present Leonardo as a man who could provide solutions to the duke’s problems? Do Leonardo’s proposals seem practical?

Most illustrious Lord. Having now sufficiently seen and considered the proofs of all those who count themselves masters and inventors of instruments of war, and finding that the invention and working of the said instruments do not differ in any respect from those in common use, I shall endeavour without prejudice to anyone else to explain myself to your Excellency, showing your Lordship my secrets, and then offering at your pleasure to work with effect at convenient times on all those things which are in part briefly recorded below.

1. I have plans of bridges, very light and strong and suitable for carrying very easily, and with them you may pursue, and at times flee from, the enemy; and others secure and indestructible by fire and battle, easy and convenient to lift and to place in position; and plans for burning and destroying those of the enemy.

2. When a place is besieged, I know how to remove the water from the trenches, and how to construct an infinite number of bridges, covered ways and ladders and other instruments having to do with such expeditions.

3. Also if a place cannot be reduced by the method of bombardment either owing to the height of its banks or to its strength of position, I have plans for destroying every fortress or other stronghold even it were founded on rock.

4. I have also plans of mortars most convenient and easy to carry with which to hurl small stones in the manner almost of a storm; and with the smoke of this cause great terror to the enemy and great loss and confusion.

And if it should happen that the fight was at sea I have plans for many engines most efficient for both attack and defence, and vessels which will resist the fire of the largest cannon, and powder and smoke.

5. Also I have means of arriving at a fixed spot by caves and secret and winding passages, made without any noise even though it may be necessary to pass underneath trenches or a river.

6. Also I will make covered cars, safe and unassailable, which will enter among the enemy with their artillery, and there is no company of men at arms so great that they will not break it. And behind these the infantry will be able to follow quite unharmed and without any hindrance.

7. Also, if need shall arise, I can make cannon, mortars, and light ordnance of very useful and beautiful shapes, different from those in common use.

8. Where the operation of bombardment fails, I shall contrive catapults, mangonels, trabocchi, and other engines of wonderful efficacy and in general use. In short, to meet the variety of circumstances, I shall contrive various and endless means of attack and defence.

10. In time of peace I believe I can give perfect satisfaction, equal to that of any other, in architecture and the construction of buildings both private and public, and in conducting water from one place to another.

Also I can carry out sculpture in marble, bronze or clay, and also I can do in painting whatever can be done, as well as any other, be he who may.

Moreover, the bronze horse may be taken in hand, which shall endue with immortal glory and eternal honour the happy memory of the Prince your father and of the illustrious house of Sforza.

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

Source: Leonardo da Vinci, Notebooks, ed. Thereza Wells (New York: Oxford University Press, 2008), pp. 275–277.

QUESTIONS TO CONSIDER