I know, hehe :)
Here is a very similar coin i found: https://www.numisbids.com/n.php?p=lot&sid=1245&lot=911
But supposed "S" on your coin is very damaged ... If it is an "S" at all ? However in my link the inscription and cross match i think.
YEAH! That's the one . The S has the same characteristics. The cross and the writing are the same . And that little oval thingy above the cross too. Thanks!
I'll want to add it to the catalogue!!
As a matter of fact , you said you will add the one you had . Where did you put it ? So I can know for this one . Because I searched for Siena and found nothing.