Complex sentence: According to Wullschlager, story ideas remained in Andersen's mind sometimes for years before coalescing with an event or mood in his life and telling stories such as "The Snowman" was a compulsion with him.
Split into simpler sentences: According to Wullschlager, story ideas remained in Andersen's mind sometimes for years before coalescing with an event or mood in his life. Telling stories such as "The Snowman" was a compulsion with him.