Margareta Gyllenstierna af Fogelvik, was a politically active Swedish countess, married to Arvid Horn, the President of the Privy Council Chancellery and one of the leading figures of the Swedish Age of Liberty.
Background
Margareta Gyllenstierna was the 6th of 10 children of count Nils Karlsson Gyllenstierna (1648-1720) and Anna Christina Gyllenstierna af Björksund (1657-1715): her year of birth is not stated, but it is likely 1689, as she was born in between her sisters Sidonia (1688-1701) and Charlotta (1690-1695).
Career
Being the only child so survive to adulthood, she was the heir of great estates in Småland and Östergötland. Gyllestierna was among the influential political spouses who collaborated with the French ambassador Charles Louis de Biaudos de Casteja, who was known to engage female agents in Sweden for France, such as Charlotta von Liewen and Hedvig Catharina Lillie. Margareta Gyllenstierna gave Casteja information and analyses about which people who was in a politically favourable position, and she further more accepted supplicants through Casteja.
The collaboration between Gyllenstierna and Casteja was broken on her initiative when the policy of Horn clashed with French interests, and she chose the interests of Horn before that of France.
Margareta Gyllenstierna maintained a political correspondence with the queen of France, Marie Leszczyńska, and the former Polish queen, Catherine Opalińska, both of whom were known as acquaintances of Horn since their stay in Sweden in 1709-1714.
Politics
Casteja often mentions her in his reports and refers to her influence of her powerful spouse by describing the political views of Count Horn as the views of the Count and Countess Horn, as if they were one joint politician who shared the position of Arvid Horn.