Nikolaus Johann van Beethoven

Nikolaus Johann van Beethoven (1776–1848) was the youngest brother of renowned composer Ludwig van Beethoven. Born in Bonn, Germany, he trained as a pharmacist and later moved to Vienna, where his older brothers Ludwig and Kaspar resided. He worked as a pharmacist's assistant before opening his own pharmacy in Linz by 1808.

During the Napoleonic Wars, Johann supplied medical provisions to French troops stationed in Linz, which bolstered his career. In 1812, he married Thérèse Obermeyer against Ludwig's objections, though the union was childless. Later that decade, Johann purchased Schloss Wasserhof estate in Gneixendorf and humorously referred to himself as a "landowner" in a letter to Ludwig, who signed back as a "brain owner."

Johann's personality and appearance differed markedly from his brother Ludwig, with contemporaries noting his eccentricity. In 1826, Ludwig visited Johann at Gneixendorf and completed the finale of his String Quartet Op. 130 during this stay.