Question about a coin from Sclavonia

I have the following coin below:

Obv: MONETA REGIS P SCLAVONIA+
Rev.: S - L
Weight: 14g
Diameter: 31mm

I had this piece since I was a child in the 1970s. I got it from a Yugoslav guest worker. The surfaces look very convincing, with the dark green patina. However, I suppose it is a modern fake or restrike or fantasy. Does anybody know more about it? Did such large bronze coins exist in 13th century Slavonia?





I took a couple of close-up pictures:

 

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https://en.numista.com/catalogue/in...&v=&i=&b=&d=&u=&a=&dg=&m=&f=&t=&w=&mt=&g=&se=

 

Yes, these are the well-known marten-denars. The question is have they also produced large copper coins?