1st - I noticed this was your very first post - so, Welcome Aboard Zerrocool! You didn't list your state (or country) in your profile. So, you might consider jumping over to Sub-Forums: Select Your Area.... and selecting location information (i.e., clubs, hunts, finds, legends, maps, etc.) directly related to your state (or country).
2nd - I moved this thread from Today's Finds! over to Forum: What Is It? for more exposure.
Its a silver hammered medieval coin. Although I can read most of the letters I can't ID it.
The sword side has the word 'CASTRUM' & the other side normal after the X 'MAUSTIS' would be the rulers name. Although I have no idea what Country to start looking in because the OP has given us nothing.