Can somebody help me identify it?

I found that coin in my attic. I was wondering what it is? I made some research but I didn't find it or at leased I wasn't sure (I think that it says constan tinopolis, starting from the right of the bust and continuing to the left side of it, you can read 'tino' on the left of the bust). I think the coin is bronze and its around 17-18mm.

Welcome to Numista!!
It look like a roman coin.
The name of the emperor starts at the right of the bust.
I am not an expert on these coins, but you can try to find it on Wildwinds:
http://www.wildwinds.com/coins/
At the bottom of the right picture I see the mintplace  ?SIS