The Renaissance Entrepreneur

My most illustrious Lord,

I have sufficiently seen and examined the inventions of those who count themselves makers and masters of instruments of war, and I have found that in design and operation their machines are in no way different from those in common use. I therefore make bold, without ill-will to any, to offer my skills to Your Excellency, and to acquaint Your Lordship with my secrets, and will be glad to demonstrate effectively all these things, at whatever time may be convenient to you...

So begins Leonardo da Vinci's letter of introduction to the Duke of Milan, Ludovico Sforza, upon his arrival in Milan in the early 1480s. Leonardo sought the duke's patronage to fund his artistic-engineering endeavors. In this letter, he then proceeds to list said instruments, which are as follows:

I have methods for making very light and strong bridges...

...remove water from the trenches...

...destroying any fortress or redoubt...

...certain types of cannon, extremely easy to carry...

...silently making underground tunnels...

...make armored cars, totally unassailable, which will penetrate the ranks of the enemy with their artillery...

...make cannon and mortar and light artillery...

...devise catapults, mangonels, caltrops, and other wonderfully effective machines...

...many kinds of highly efficient machines for attack and defense, and vessels...
(Nicholl, 2004)

According to Nicholl's Leonardo da Vinci, Flights of the Mind, a Biography, from which this passage is taken, "there is no evidence that any of these machines ever existed except on paper." It looks like Leonardo was a bit of a sci-fi entrepreneur. How else could a multi-talented Renaissance polymath earn a living in end-of-millennium Italy?

The images accompanying this post are facsimiles of one of Leonardo's small notebooks in which he doodled and jotted down observations in his characteristic left-handed mirror script. They are true to size, so handling them feels very neat, as if one is holding the real thing. The book has several notebook replicas, and I find them very inspirational because through them, I get a sense of Leonardo's passion for his work.

He summed up his letter to the Duke of Milan thus:

In short, I can contrive any infinite variety of machines for attack or defense... in painting I can do everything that it is possible to do
(Nicholl, 2004).