  It was a striking curiosity of Rehberg's cultural milieu that his father was a close friend of Johann Adolf Schlegel, the father of August Wilhelm and Friedrich Schlegel, two founding spirits of Romanticism.  The families would often meet, and so the little Rehberg would often romp with the Schlegel kids.  As it happened, Rehberg's younger sister Caroline became the first love of Friedrich Schlegel, who immortalized her as Luise in his Lucinde. During one of the family outings, Caroline sketched a drawing of the young Friedrich Schlegel, which now introduces the critical edition of his  works.[10]  If the Rehbergs inspired the Schlegels, the Schlegels did little for Rehberg.  Known for his dry, sober and puritanical temperament, Rehberg distrusted the self-indulgence and libertinism of Romanticism.  He always kept his critical distance from Romanticism when it spread throughout Germany in the early 1800s.  The best indicator of his attitude toward Romanticism is his review of some of Adam Müller's writings, in which he deplored their mysticism and  obscurantanism.[11] 