Castell Texas began in 1847 as a land grant in Comanche territory settled by German abolitionists and Free-Soilers. Before Castell Texas was settled the land had formerly been part of the Fisher-Miller Land Grant. It was part of a series of five immigrant settlements sponsored by a group of prominent Germans known as the Adelsverein, including Count Emil von Kriewitz, John O. Meusebach, Prince Carl of Solms-Braunfels, Hermann Spiess, Gustav Schleicher, Ferdinand Ludwig Herff, and Count Carl Frederick Christion of Castell-Castell (1801–1850).
Count Castell was the Vice President and Business Manager from the beginning of the Adelsverein until about the time of Castel’s founding. The other communities were Schoenburg, Meerholz, Leiningen, and Bettina. The first two were unsuccessful from the start. Leiningen and Bettina had brief lives, with Bettina lasting only a year. Only Castell remains in Llano County.