Ivory medallions with portraits of King Jan III Sobieski and Maria Kazimiera

Both medallions are oval-shaped portraits carved of ivory, in a gilded octagonal frame with a semicircular suspension hook.
One of them depicts King Jan III Sobieski. He is portrayed without a crown, wearing a coat and a karacena, i.e. armour made of iron scales. An inscription on the back side: “Johannes III D.G. / Rex Polonia. Magni. / Dux Lith”.
The other portrait shows Maria Kazimiera de La Grange d’Arquien, wife of King Jan III Sobieski. She is wearing a dress with puff sleeves, and a low neckline. There are strings of pearls on her neck, and her hair is artfully curled. An inscription on the back side: “Maria Casimira D.G. / Regina Polonia et / Magn. Duc. Lith.”