Probably David Robert's deceased sale, London, Christie's, 13 May 1865, lot 102;
With M.R. Schweitzer Gallery, New York;
Where acquired by the late owner in 1967.

The paper support has been laid on canvas and the paint surface has perhaps been slightly pressed in the process though is otherwise well preserved beneath a dirty, yellow varnish. A reading under UV is impeded by the old streaky varnish but there is possible old strengthening to the darks of the vaulted ceiling and to the left edge. The painting would benefit from a light clean and revarnish. Offered in a simply carved gilt wood frame.
In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective qualified opinion.
NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING CONDITION OF A LOT, ALL LOTS ARE OFFERED AND SOLD "AS IS" IN ACCORDANCE WITH THE CONDITIONS OF SALE PRINTED IN THE CATALOGUE.

Another sketch by David Roberts of Milan cathedral, showing the bronze pulpits in more detail and with figures in the foreground, can be found in the Victoria and Albert Museum, London (inv. no. 79-1881).  That picture is considered to date to the early 1860s.