Margaret Theresa of Spain was, by marriage to Leopold I, Holy Roman Empress, German Queen, Archduchess of Austria and Queen of Hungary and Bohemia. She was the daughter of King Philip IV of Spain and the elder full-sister of Charles II, the last of the Spanish Habsburgs. She is the central figure in the famous Las Meninas by Diego Velázquez, and the subject of many of his later paintings.

Leopold I was Holy Roman Emperor, King of Hungary, Croatia, and Bohemia. The second son of Ferdinand III, Holy Roman Emperor, by his first wife, Maria Anna of Spain, Leopold became heir apparent in 1654 after the death of his elder brother Ferdinand IV. Elected in 1658, Leopold ruled the Holy Roman Empire until his death in 1705, becoming the second longest-ruling Habsburg emperor. He was both a composer and considerable patron of music.