Maria Isabella of Portugal (1797-1818) was the daughter of King John VI of Portugal and Infanta Carlota Joaquina of Bourbon-Spain. She was bestowed with the Royal Order of Maria Luisa of Spain in 1801. In 1816 her marriage to her maternal uncle, King Ferdinand VII of Spain, was arranged with the aim of strengthening ties between the two countries. The marriage produced no heirs and she died only two years after their union, following a complicated pregnancy. She was noted for her love of the arts and her interests led to the the formation of a royal museum, opening a year after her death in 1818, and later became the Prado Museum in Madrid.
A very similar unsigned miniature in a feigned oval was offered for sale at the Dorotheum, Vienna, 18 November 1998, lot 311 (sitter unidentified).