Charles Augustin Busby (1786-1834) is chiefly known today as the principal architect of Regency Brighton and Hove. He trained in the office of the architect and engineer Daniel Alexander and went to classes at the Royal Academy. Amongst his early projects, at the age of 23 he designed the Commercial Coffee Rooms in Bristol in imitation of Soane's Three-percent Office at the Bank of England built a decade earlier. Busby's experimental design for a roof led to the collapse of one of his buildings and his subsequent departure for American in 1817. There he was based in New York and attempted to set up the equivalent of the Royal Academy. He studied American prisons and penitentiaries making a series of measured drawings and he spent time in Washington where he visited the architect Charles Bulfinch and made copies of his drawings for the unfinished Capital Building. He also drew bridges in Philadelphia. As Baltimore is midway between Philadelphia and Washington this sample must have been acquried on one of these trips. In his years in America he built only one building, in Virginia. He returned to England in 1820 and moved to Brighton in 1823.

In the Soane Archive (Priv. Corr. I.B.23.9) is a sheet of paper with the following statement signed by Busby, which must have accompanied the specimen when it was acquired by Soane:
The American Verde Antique, was discovered a few years past in an abundant quarry a few miles from the City of New Haven in the State of Connecticut by a young Student of Yale College. The largest Specimen I have seen consists of a Tablet about four feet diameter, highly polished, deposited in Yale College, New Haven, in the collection of Col. Gibbs of New York.
Marble is abundant in the vicinity of New York, Philadelphia and Baltimore, it is white but of a coarse grain. Marble of a superior fineness is said to exist in the lower beds, and occasional pieces of moderate dimensions and beautiful texture are often met with in the present state of the quarry. The present specimen is taken from one of these pieces, which was found near the City of Baltimore.
C.A. Busby / May 1821.

Busby and Soane knew each other professionally as is attested by a letter of October 1809 from Busby in the Soane Archive asking if he can mention his name in connection with the project for the Bristol Commercial Rooms (in the letter he refers to it as 'a Coffee-Room in Bristol') constructed in 1810 (Bolton, The Portrait of Sir John Soane, 1927, p.140). They probably met through the Royal Academy where Busby won the Gold Medal for architecture in 1807 with a design for a building for three learned societies (the RA, RS and Society of Antiquaries).

C.A. Busby The Regency Architect of Brighton and Hove, RIBA Heinz Gallery exhibition leaflet, 1991 [text by Neil Bingham]