This cipher was used by the Doge of Venice Michele Steno in a diplomatic message in 1411. See this page for the history of this cipher and how it was recovered.
It is a small nomenclator, one of the first in Europe, consisting of an alphabet with homophones, a good number of nulls, and a small dictionary.
The cipher was reconstructed comparing clear and encrypted text and is therefore almost certainly incomplete; it could contain other homophones, other nulls and above all other words of the dictionary, not used in this dispatch.
On the right the reconstructed cipher divided into three tables: alphabet, nulls and dictionary.
The tables on the side use an ad hoc font, which is visible on the web only using latest browsers updated to css3 style sheets, otherwise Latin letters are visible, more or less similar to the cipher signs; alternatively you can choose the graphic mode, where the signs are visible anyway, with any browser.
The interactive example on the side allows you to encrypt a short sentence (max 32 letters) using the cipher of Michele Steno.
Homophones are chosen at random, using a random function, so the encryption can be different each time the page is reloaded. The system uses the 20-letter Latin alphabet: ABCDEFGHILMNOPQRSTVX* and the ad hoc fonts, see above. Other letters will be discarded or replaced.