It's a silver 1/24 thaler, or 3 groschen, from Poland under Sigismund III. Can't make out the second numeral of the date clearly, but 1620's. Despite the age these are actually very common.
There are only the last two numerals. If you look at the first photo where there is a "24" in a circle in the center. At about 10 o'clock just outside the thick inner circle is a "2" and at 2 o'clock is the other numeral. Looks like it may be a 1 for 1621, but again I can't make it out clearly.
