Complex sentence: Louis XIV had died on 1 September and Madame de Berry, officially in mourning, promised she would not attend any shows for six months, but she soon openly turned into a "merry widow".
Split into simpler sentences: Louis XIV had died on 1 September and Madame de Berry officially in mourning, promised she would not attend any show for six months. But after the death of the Sun King, she openly turned into a "merry widow".