Same thing, it's used along with the "imparfait". A little more info: "The passé simple, translated in English as either "simple past" or "preterite," is the literary equivalent of the passé composé, which means that it is used only in formal writing (e.g., historical and literary writing) and very formal speech. In such writing and speech, the passé simple is used alongside the imperfect, just as in everyday speech/writing, the passé composé and imperfect are used together." http://french.about.com/od/grammar/a/passesimple.htm