Every now and then I idly search Google for names in my family tree and seeing if anything pops up. Yesterday I was searching for Gideon Moyer, an x-great uncle, specifically because his name is so rare. One of the hits that instantly jumped out at me was from Google Books: Lebensbild aus dem Pennsylvanisch-Deutschen Predïgerstand. It is a transcription (in German) of William Helffrich's journal as a pastor in the Lehigh Valley. It has quite a few direct references to the Moyer clan, making it indispensable. I made a few discoveries as I searched through it, but one made my heart race.
My 3rd great grandmother, Catherine Gerard (also spelled Girard or Gernard)--wife of Peter Moyer--came to America with her mother when she was a girl, and had to work as an indentured servant for years to earn their freedom. I had established, from several sources, that she was born in Württemberg, but one of my main genealogical goals is to trace my ancestors back to specific European cities. This is very hard. And yet, there in Helffrich's journal, the city of Catherine's origin could not have been more exactly pinpointed. Here is the original text:
Am 4. April beerdigte ich Mutter Peter Moyer in Lynn; sie war am 30. April 1804 in Sengach, Maulbronn, Württemberg, Europa, geboren. Mutter Moyer war ein Muster von einer christlichen Hausfrau und so lange ihr Gatte lebte, war ihr Haus mein stetes Absteigequartier, wo ich immer mit Liebe und Zuvorkommen aufs freundlichste eingeladen und aufgenommen wurde.And here is a pretty reasonable Google translation:
On 4 April  I buried mother in Lynn Peter Moyer, it was on 30 April 1804 in Sengach, Maulbronn, Württemberg, Europe was born. Moyer mother was a model of a Christian housewife and her husband lived for so long, their home was my steady flophouse district, where I was always received with love and courtesy in the friendliest and invited.Not sure about that "flophouse" part, but overall that paints a very nice picture of Catherine and her husband. And she was born in Sengach, Maulbronn, Württemberg. Maulbronn was easy to locate, but I had distinct trouble finding Sengach, meaning it was either an outdated name or a tiny hamlet. It turned out to be the second.
I managed to find it listed on a weather site, with coordinates included. It is right next door to Maulbronn, so I have high confidence that it is the right place.
Now I have a place to start looking in German parish records.