Tove Jansson after Tove had become an adult, the two often traveled together, and during her final years Signe also lived with Tove part-time. Jansson is principally known as the author of the Moomin books. Jansson created the Moomins, a family of trolls who are white, round and smooth in appearance, with large snouts that make them vaguely resemble hippopotamuses. The first Moomin book, "The Moomins and the Great Flood", was written in 1945. Although the primary characters are Moominmamma and Moomintroll, most of the principal characters of later stories were only introduced in the next book, so "The Moomins and the
Finnish name share the same surname. All persons have the right to change their surname once without any specific reason. A surname that is un-Finnish, contrary to the usages of the Swedish or Finnish languages, or in use by any person resident in Finland cannot be accepted as the new name, unless valid family reasons or religious or national customs give a reason for waiving this requirement. However, persons may change their surname to any surname that has ever been used by their ancestors, if they can prove such claim. Surnames behave like regular words when forming grammatical cases. Thus, for example,