With a coin in such a condition it would be difficult to say without prior cleaning. I can only point you in a direction of your own further research. And this direction would be countries around the Baltic sea. Sweden or Lithuania or Poland Solidus from 16th - early 17th century would be most probable. Billon solids/schillings of the time due to the minting process were often off-center. Polish solids and 1/2 or 1 groschen have eagles on them (there seem to be a lower part of the eagle visible on your coin). A few links below might help. http://baracinka.at.tut.by/kat_pol.html http://www.mcsearch.info/record.html?id=1093908 https://www.google.com/#newwindow=1&q=sweden+poland+lithuania+solidus+image&tbm=isch
I collect coins and tokens which circulated in Africa from 18th century to 2000. I sell about 7000 illustrated world coins from http://www.avscoins.com.
