caused Wagner to assign a more commanding role to music in his later operas, including the latter half of the Ring cycle, which he had yet to compose. Aspects of Schopenhauerian doctrine found their way into Wagner's subsequent libretti. A second source of inspiration was Wagner's infatuation with the poet-writer Mathilde Wesendonck, the wife of the silk merchant Otto Wesendonck. Wagner met the Wesendoncks, who were both great admirers of his music, in Zürich in 1852. From May 1853 onwards Wesendonck made several loans to Wagner to finance his household expenses in Zürich, and in 1857 placed a cottage on his estate at Wagner's disposal, which became known as the Asyl ("asylum" or "place of rest"). During this period, Wagner's growing passion for his patron's wife inspired him to put aside work on the Ring cycle (which was not resumed for the next twelve years) and begin work on Tristan. While planning the opera, Wagner composed the Wesendonck Lieder, five songs for voice and piano, setting poems by Mathilde. Two of these settings are explicitly subtitled by Wagner as "studies for Tristan und Isolde". Among the conducting engagements that Wagner undertook for revenue during this period, he gave several concerts in 1855 with the Philharmonic Society of London, including one before Queen Victoria. The Queen enjoyed his Tannhäuser overture and spoke with Wagner after the concert, writing of him in her diary that he was "short, very quiet, wears spectacles & has a very finely-developed forehead, a hooked nose & projecting chin." In exile: Venice and Paris (1858–1862) Wagner's uneasy affair with Mathilde collapsed in 1858, when Minna intercepted a letter to Mathilde from him. After the resulting confrontation with Minna, Wagner left Zürich alone, bound for Venice, where he rented an apartment in the Palazzo Giustinian, while Minna returned to Germany. Wagner's attitude to Minna had changed; the editor of his correspondence with her, John Burk, has said that she was to him "an invalid, to be treated with kindness and consideration, but, except at a distance, [was] a menace to his peace of mind." Wagner continued his correspondence with Mathilde and his friendship with her husband Otto, who maintained his financial support of the composer. In an 1859 letter to Mathilde, Wagner wrote, half-satirically, of Tristan: "Child! This Tristan is turning into something terrible. This final act!!!—I fear the opera will be banned ... only mediocre performances can