 With respect to the Leibnizian-Wolffian philosophy, there is significant evidence of women’s extensive engagement with the system already at its origins. Leibniz exchanged letters with a number of women, but his correspondence with his patroness Electress Sophie of Hanover (1630–1714), who happened to be the sister of Elisabeth of Bohemia, and her daughter Queen Sophie Charlotte of Prussia (1668–1705), is particularly significant as it frequently turned to philosophical topics. In his letters, and his personal exchanges with “the two Sophies”, Leibniz can be seen to refine and develop key doctrines, including his conception of substance and his attempted theodicy (Strickland 2011: 35–48), where Leibniz himself claimed that his Theodicée found its beginnings in his conversations with Sophie Charlotte. Sophie of Hanover likewise supplied Leibniz with one of his favourite pieces of empirical evidence for the principle of the identity of indiscernables (when she challenged a courtier to find two identical leaves during a garden stroll). Sophie of Hanover was no dogmatic Leibnizian however, as she maintained her commitment to physical influence between the mind and the body, and hosted controversial figures such as Francis Mercury Van Helmont (1614–1699) and John Toland (1670–1722) at her court. It is, however, debated whether Sophie shared the materialist views of these thinkers when it comes to the mind (de Careil 1876; Strickland 2009 and 2011: 49–64) or instead upheld a metaphysically agnostic view regarding the nature of the soul (Leduc 2021).