The question is asked in the context of theories about the use of 'millions' or 'milioni' in association with Marco Polo and the reason for the use of the word as the Italian title for his book, known in English as 'The Travels of Marco Polo' and the Ca' Polo, which is still known as the 'Corte del Milion'.
One of the theories (cited in Moule and Pelliot (1938), p 32, note 3) is that it is an Italian version of Aemilius and that it was Marco's name.
Another that it was on account of either his excessive use of the word or his exaggeration in telling stories, although the word does not appear in his book. (Moule and Pelliot (1938), p 33, note 1), (Yule (1871) p xciv f).
Another that it was because the Ca' Polo was bought for a million (Yule, as above).
These are all credible and substantiated. There is another theory put forward by Benedetto, in his 1928 edition of the work, however, which is that it is based on the family having originated in 'the Venetian Sestiere of Emilione'. (as quoted in Markus and Munkler).
I haven't been able to verify Benedetto's account directly, to see whether he meant a Venetian sestiere, or a region near Venice (eg Emilia-Romagna / Reggio Emilia / Castelfranco Emilia) nor have I been able to find any mention of a Venetian Sestiere called 'Emilione'.
So - my questions are:
1) Is there any record of such a district existing in Venice? I can find no reference to it on contemporary or historic maps I've looked at to date. Nor have I found a reference to a Church of Santa Emilia there, for example.
2) Is there any evidence to connect the Polo family with any of the 'Emilia' regions?