Useful Exercise?

[pfeaster]

Anybody fancy trying to decipher the following letter. It is dated to 1440 and from Milan.

It looks like it's already been deciphered: nihilominus arca hec et alia quedam nonnulla latius intimabo... ("nevertheless, I will describe this box and some others in more detail..."), etc., etc.

But is the challenge for us to work out a key to the cipher based on the decipherment?  That could be interesting.

To kick things off: that first word nihilominus occurs again later in the message, and there's a matching sequence of cipher characters both times, but the repeated part starts a few characters into the ciphertext.