Searching for documents at your relatives' house

Years ago as a young kid at my grandmother's house, I stumbled upon a book in the living room shelves: it was a bible, in german (and gothic print).

I remember it had some names on it. After investigating with my grandmother, I started scribbling an original family tree on that side. I must have been about 10 years old.
Actually the bible was a present to Immanuel Gotthold TZSCHABRAN on his wedding day to Clara WIESE. They married in the military barracks church in Frankfurt an der Oder (Gotthold was a officer in the Imperial army).

It has additional information: Gotthold was born in Pitschen (see dot 1 in the map), and Clara was born in Wehlau, now Znamensk in Russia (dot 3). Their wedding was in Frankfurt/Oder (dot 2). (Microsoft MapPoint is a very useful piece of software for genealogy!)

Finally, the book has a picture of Martin Luther, another indication of were to do my research in Germany today, had I not known that part of that family was Lutheran.

I finally got my grandmother to give me that Bible: it is safe now in the hands of the family genealogist !