Referring to the watermark in You are not allowed to view links.
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At the same site (You are not allowed to view links.
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This says Regensburg 1640, which is quite near Prague. I am not sure what is the meaning of the multiple lines in this motif, which is why more expert help will be good.
Also this one: You are not allowed to view links.
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with just the year 1663/1664 (which is very close to the date of the Marci letter).