After looking at the picture Sveta had posted, I also thought that the man on the right could be the Count of Aquila.
His sisters were
- Luisa Carlotta (1804-1844), married to Francisco de Paula Infant of Spain
- Maria Cristina (1806-1878), married to 1) King Fernando VII of Spain and 2) Fernando Muñoz y Sanchez, Duque de Rianzaro
- Maria Antonietta (1814-1898), married to Leopoldo II, Grand Duke of Tuscany, Archduke of Austria
- Maria Amalia (1818-1857), married to Sebastian Infant of Spain and Portugal
- Maria Carolina Ferdinanda (1820-1861), married to Carlos Infant of Spain
- Maria Teresa (1822-1889), married to Emperor Pedro II of Brazil
Isabella (on the left) looks quite young here. As she married in April 1850 I guess the picture was taken in the early 1850's ...
By the way: The background of this picture looks very familiar to me. I've often seen this kind of painted trees and landscape in photos showing members of the Bourbon-Sicilies ...