Good as gold. I can barely see the makers mark. It looks like it *might* be CD800, which would be Carl Dilenius, Pforzheim.
The cross was awarded during WW1. The other medal was authorized by Hitler in '34. When the vets rec'd their new '34 medal, the got out their Iron Cross and mounted them together. No "participation" medal was issued to WW1 soldiers after the war until Hitler did. By doing this, he acknowledged their efforts and gained their loyalty. Gary