Certificate of Legation

David's question is one of three he submitted about his grandfather (whose name David did not share)

In March of 1891, he was issued a "Certificate of Legation from the United States, to the German Empire" (I have this document) My take on this, is this document guaranteed his safe travel BACK to Germany and return as a United States citizen. Is this a correct assumption on this document?.

ASK OLIVE TREE response: Dear David - I personally have never seen such a Certificate. I would have to see the original document to provide a response. What agency issued it? What exactly does the document say?

It would also help to know where you obtained this document - that is, what set of records? Or is it an original document in your possession?