While serving under the Nawab Asaf-Ud-Dowlah of Awadh, Martin acquired a massive fortune of about Rs 4,000,000. He built the palace of "Constantia" and his fine house of Farhat Baksh, both of which he equipped with luxuries that included a library of some 4,000 volumes written in many languages and a picture gallery containing a fine collection of works of art. At his death, Claude's collection included over 650 Company style paintings of birds which were painted by Mughal-trained painters. "Black Stork in a Landscape", now in the Metropolitan Museum of Art in New York, is one of these.