During the 1970s Stockhausen became even more popular. This was partly because other music, like the other arts, had become political and very left-wing in the 1960s, which made people angry. It was also partly because audiences wanted a change from music that was very complicated, and Stockhausen's music had become much simpler. His most popular compositions are "Tierkreis" (1974–75) and "In Freundschaft" (1977). Stockhausen broke with his publisher and started to publish his music himself. From 1977 to 2003 Stockhausen composed "Licht" ("Light"), a set of seven operas named for the days of the week.