Wagner was a close friend — Nietzsche visited frequently, was a strong admirer of the older man, and at Christmas sent Cosima Wagner music he’d composed (the friendship did not survive his transparent attack on Wagner in print). Nietzsche had an unsettling friendship with Andreas-Salomé, driving him to the despair out of which ‘Thus Spake Zarathrustra’ was begun. A long friendship with Burckhardt began when Nietzsche was appointed to Basel University. Strindberg, Liszt, Brandes and Taine were correspondents. He was visited by Steiner when he’d been overtaken by madness.