I first heard about her in high school World History class alongside Frederick the Great. She held the Holy Roman Empire together for about a half century after being challenged by Frederick the Great, no small achievement. While at it, she had 16 children. She wasn't a leader of fashion, but she was portrayed many times. The artist who portrayed her most often was Martin van Meytens and his studio (called "van Meytens" in this subalbum). The Hungariam Web Gallery of Art has this about how van Meytens et al. portrayed Empress maria Theresia: "Martin van Meytens as a court painter had the permanent task of painting the portraits of the Emperor and the Queen, as well as of the various members of the imperial family. Since the decoration of various residences and institutes, gifts to foreign sovereigns, aristocrats and diplomats and various festive occasions made necessary several copies of the imperial portraits, these courtly representations were made in series by the workshop, and Meytens himself played only a minor or greater part in their execution. He had no occasion to make more than a study of a head after the model the Queen had neither the time nor patience to sit for the artist for a long time. This original head or bust sketch was copied with different poses, clothes and accessories for the different imperial portraits. The portrait of Maria Theresia exhibited here is very similar to her figure in the great family portrait made in 1754 (Vienna, Schönbrunn). Her pose, hairstyle, neckline, the piece of jewelry worn at the collar and the gesture of her right hand are all identical. The study which served for both pictures as a model, was copied several more times by Meytens and his workshop."
In the USA, she is probably most remembered as the mother of Queen Marie-Antoinette. Maria Theresia's Wikipedia article is here.

ca. 1740 Possibly Empress Maria Theresa of Austria and her daughter by circle of Jean-Étienne Liotard (auctioned by Christie's)

1742-1744 (some time between) Maria Theresia by Martin van Meytens the Younger (on auction by Das Kunst- und Auktionshaus Kastern GmbH & Co KG)

1743-1745 Maria Theresia of Hungary and Bohemia, Empress Consort of the Holy Roman Empire in Hungarian coronation robes by Daniel Schmiddeli (Godolloi Kiralyi Kastely)

1740s Maria Theresa as Queen of Hungary by Workshop of Martin van Meytens the Younger (Muzeum Miejskie Suchej Beskidzkiej - Sucha Beskidzka, województwo małopolskie, Poland)

1745 or later Empress Maria Theresia standing wearing a lace dress probably by Martin van Meytens (Schloß Schoenbrunn, Wien)

ca. 1755 Maria Theresia, römisch-deutsche Kaiserin by P. Castriono, nach van Meytens (Tansey Miniatures Foundation collection, Bomann-Museum - Celle, Niedersachsen, Germany)

ca. 1755 Maria Theresia, römisch-deutsche Kaiserin by P. Castriono, nach van Meytens (Tansey Miniatures Foundation collection, Bomann-Museum - Celle, Niedersachsen, Germany)
