Fredericksburg is a heavily German-influenced town. The city square is called Marktplatz, there's a "wilkommen" sign hanging from every shop door, and the main B&B booking organization is called Gästehaus Schmidt. It's Oktoberfest year-round in this hot little town, and everyone's invited!
Named for Prince Friedrich of Prussia, Friedrichburg (now Fredericksburg) was established in 1846 by Baron Ottfried Hans von Meusebach (better known as John O. Meusebach in Texas). It was the second main settlement, after New Braunfels, from the Society for the Protection of German Immigrants in Texas, or Adelsverein. This organization of German nobles brokered land in Texas to increase German emigration. Meusebach also managed to broker a peace treaty with the Comanche Indians that prevented raids and helped promote trade in the area (to this day, it is the only American Indian treaty not broken in the state). Cattle and agriculture eventually became the primary sustainable commerce in the city as it grew through the Civil War and moved into the 20th century.
In addition to the town's German roots, something else to keep in mind: Fredericksburg is primarily a weekend destination. Locals enjoy the influx of visitors, but they also say their favorite days are Sundays and Mondays because people pack up and leave, meaning that for a short while it feels like a small town again. If you want that experience, visit during the week, particularly in fall or winter.