Question: Who is the maternal grandmother of Mattias De' Medici?
Sentence (from "Archduchess Maria Maddalena of Austria"): Maria Maddalena of Austria (Maria Magdalena; 7 October 1589 – 1 November 1631) was Grand Duchess of Tuscany from the accession of her husband, Cosimo II, in 1609 until his death in 1621.
Relevant evidence: No