Complex sentence: After the death of the queen in 1583, she was given the equivalent position at the court of Princess Anna Vasa of Sweden, in which she is mentioned in 1587, when the next Mistress of the Robes to the queen of Sweden is also recorded.
Split into simpler sentences: After the death of the queen in 1583, she was given the equivalent position at the court of Princess Anna Vasa of Sweden. She is mentioned in this position in 1587, when the next Mistress of the Robes to the (new) queen of Sweden is also recorded.