It's an Italian word. Do as the author has here and place it in italics. No initial cap.
https://books.google.co.uk/books?id=lRBJAgAAQBAJ&pg=PA157&lp...
... a stipend that also gave its recipient a semi-official profile as the leading painter of the Venetian state.

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Note added at 37 mins (2016-09-16 01:24:06 GMT)
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Another reference: https://books.google.co.uk/books?id=RQM5JjFqlmsC&pg=PA275&lp...


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Note added at 39 mins (2016-09-16 01:26:14 GMT)
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The leading artists of Venice could aspire to an established, salaried civic position, the sansaria...
https://books.google.co.uk/books?id=FrcsXlpD6NIC&pg=PA271&lp...

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Note added at 12 hrs (2016-09-16 12:47:13 GMT)
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I'm not sure why you have directed your enquiry exclusively to EdithK, but here is my contribution.
sansaria is the Venetian form of the Italian word sensaria. Wiktionary defines this as:
senseria f ‎(plural senserie)
1) agency (the activities of an agent)
2) remuneration, brokerage (paid to an agent)
You could therefore write
...sansaria (brokerage)...

I do not consider 'mediation' to be appropriate for your context as the modern sense of this word is more associated with marriage counselling.