 It was there that Wagner resumed work on "Siegfried" in May 1857.In August 1858, however, Wagner was forced to leave Zürich alone, following an argument with Minna over his questionable relationship with Wesendonck's wife Mathilde; he and Minna were formally separated in 1862, though Wagner continued to support her financially until her death in 1866.From 1858 to 1864 Wagner spent six restless years wandering across Europe.