 With Engel, Humboldt read and discussed works by Leibniz, Hume, Locke, Harris, Herder, Condillac and Rousseau. Yet at the same time both Humboldt brothers were deeply immersed in the study of the Greeks. Wilhelm’s first publication (at the age of 19) dealt with Socrates and Plato’s idea of divinity (“Socrates und Plato über die Gottheit”) in which he defended the enlightenment ideal of natural religion. As adolescents the two brothers began frequenting the literary salon of Markus and Henriette Herz in Berlin where they came into contact with intellectual luminaries of the city. It was here that Wilhelm first met Moses Mendelssohn’s eldest daughter Brendel Veit, the subsequent Dorothea Schlegel, Schiller’s future spouse Charlotte von Lengefeld and his own bride-to-be, Karoline von Dacheröden. After only one disappointing semester at the narrow and provincial Prussian University at Frankurt-on-Oder, the Humboldt brothers transferred to the University of Göttingen in 1788, arguably the most distinguished University in all the German-speaking territories at the time. Besides jurisprudence, Wilhelm studied classical philology with Christian Gottlieb Heyne, natural science with Georg Christoph Lichtenberg (who counted him “among the brightest intellects” he had ever met), and immersed himself deeply in the study of the philosophy of Immanuel Kant. In Göttingen he met and became friends with August Wilhelm Schlegel, George Forster and the philosopher Friedrich Jacobi. In August 1789 shortly after the outbreak of the French Revolution and accompanied by his former teacher Campe, Wilhelm visited Paris, the Rhineland and Switzerland and captured his observations in a travel journal that he kept (GS Vol 14: 76–236). In response to the challenge of the encounters with Forster and Jakobi, Humboldt was lead to articulating his own philosophical position in “On Religion” (“Über Religion”, GS Vol 1: 45–76), his first important writing.