Merchant's House is a heritage-listed education centre and offices at 43–45 George Street in the inner city Sydney suburb of The Rocks in the City of Sydney local government area of New South Wales, Australia. Its design is attributed to John Bibb and was built during 1848. It is also known as Counting House (former) and Merchant's. The building formerly served as a residence, museum, offices and boarding house. The property is owned by Property NSW, an agency of the Government of New South Wales. It was added to the New South Wales State Heritage Register on 10 May 2002.

History The first buildings in the vicinity were the hospital and the houses of the surgeons. The hospital was immediately to the south of the Merchant's House. By 1802 Nicholas Bayly built a substantial house with a distinctive mansard roof for himself on the eastern side of High Street more or less in front of the site. This was followed shortly by the house of Robert Campbell, also on the eastern side of the road.

The first documented occupation of the site of the Merchant's House following European arrival was the leasing of the land by Captain Waterhouse. His lease, shown on Grimes' map of 1800, occupies both sides of the alignment of the High Street. Waterhouse was a naval captain, having served on the First Fleet ship Sirius as midshipman. He returned to England and took part in naval actions but was encouraged to return to the colony, importing the first merino sheep. His grants included land at Liberty Plains and Parramatta, and leases within Sydney at The Rocks and Garden Island. He returned to England for the last time in 1800. No permanent structures can be seen in paintings or drawings that show his land.

Robert Campbell arrived in Sydney in 1798 from India where he worked as a merchant and trader in a family business. His arrival and enthusiasm to become established as a resident trader gave him strong support from Governor Hunter. Buying land at Dawes Point, he began to erect warehouses, wharves and a home for himself, and began to develop importing lines that were still the only source of some essential supplies. To provide for paying return cargoes, he encouraged the sealing industry. He also took over Captain Waterhouse's leases, eventually converting them into freehold granted land, which resulted in him controlling a substantial part of Dawes Point, with Campbell's Cove becoming part of the named harbour landscape. The focus of Campbell's activities was on the water's edge, with facilities for ships and warehousing. The landscape of the peninsula included a substantial brick wall that surrounded his land from George Street to Gloucester Street. The land within it appears to have been cleared but remained the original rocky slope.

Detailed maps of 1822, 1831 and 1836 do not show any structures on the land, but by 1843 the effects of subdivision by Campbell are shown with houses dotting the periphery of his land. The Merchant's House land was granted to Robert Campbell on 16 October 1834, following a long period as Campbell's lease. By this time Campbell had expanded his business greatly, starting grazing stock in the Monaro and Western Plains. He was also an original shareholder of the Bank of New South Wales. Campbell is remembered positively by history, with a reputation for fairness in trade and not using his power as one of the major merchants to unduly influence the political landscape. Campbell died in 1846.

The early 1840s were an economic depression in NSW, resulting from the gradual cessation of transportation and consequent rise in labour costs, severe repeated droughts and especially the pain of transforming from a state-subsidised to a mercantile economy. Although Campbell is recorded as having weathered the depression better than most of the bigger traders, he still chose to subdivide his land. While Campbell owned the area back from Campbell's Cove, its use and ultimate value were restricted to a narrow maritime trading function. Selective subdivision allowed him to raise capital without compromising the way his trading base operated. In 1841 he subdivided and placed for sale blocks of land bounded by George Street, Atherton Place and Gloucester Street. One allotment, No. 4, was conveyed to John Martyn and James Combes for £825 in June 1841. This was the southeastern corner block of Campbell's land and located on the northern corner of George Street and a small lane, initially called Union Lane. Martyn and Combes erected a three-storey building on the corner, with a matching partner for it being erected at about the same time on the opposite corner of the lane. The north corner building of George Street and Atherton Place became No. 47 George Street. The matched buildings were designed by John Bibb.

Martyn and Combes operated as plumbers, painters and glaziers in a building only down George Street on the corner of Jamison Street, but clearly had enough capital to invest in a substantial construction. Several years later, after Campbell's death in 1846, his son George sold the neighbouring allotment No. 5 to Martyn and Combes as well, for the sum of £300. Allotment 5 became Nos. 43-45 George Street, although different numbering was used during the later 19th century.

Martyn and Combes erected the Merchant's House by September 1848. They were described as 'newly erected stone built premises, situate in George-street North, opposite Messrs. Campbell's, consisting of a commodious dwelling house and spacious stores, replete with every convenience'. It was noted as having stone walls, three floors, a slate roof and a frontage onto George Street.

Both No. 47 and Nos. 43–45 had been built with the intention of being leased or let to other users. Sydney Cove became busier during the 1840s as the success of the wool industry brought wealth, trade goods and encouraged immigration. Investing in the infrastructure of trade may have been a gamble in 1841 but would have been proven a safe bet seven years later. The first known occupants of 43–45 were Lawrence and Steven Spyers, operating as merchants and commission agents, occupying both the house and the store in 1850. Two years later the residence was occupied by Archibald Walker, a merchant, and Martyn and Combes occupied the store.

Martyn occupied the residence from 1859 until his death in 1864, and the store by Martyn and Combes. The two buildings Nos. 43–45 and No. 47 appear to have been treated as a single entity by Martyn and Combes as is shown in detailed plans which begin to appear in this period. The death of John Martyn signals the start of a rapid turnover of tenants and occupants. After John Martyn's death, his son William ran the business in the store, but the residence was occupied by William Rielly in 1865–1867.

The Merchant's House itself was suitable as a residence for respectable business men. The succession of soap manufacturer and manufacturing chemist suggests that the place with the adjoining store was also suited for that type of light industry, even though it did not directly reflect The Rocks' maritime or mercantile character, unlike the wool brokers and merchants who needed to be near the port. That these presumably aromatic trades could be carried out next to residences suggests that the expectations of tenants were not too high.

Edward Row and Co. initially occupied No. 47, and then expanded into No. 45 in 1876, and by 1882 they had also taken over the residence. Row is listed as a wholesaling and manufacturing chemist. Little is known of the firm Edward Row apart from their products. Their earlier offices mentioned in advertisements are in King Street and Bank Court, Sydney, and the proprietors were John and Edward Row. One advertisement quotes them as being established in 1820. As a wholesaling and manufacturing chemist it is likely that Row produced their own and on-sold other manufacturers' products, possibly taking in bulk volumes and packaging it for the colonial market.

Row's Embrocation was probably their major product, judging by its appearance as a large lettered sign on the northern face of No. 43 in the later 19th century. It was a dressing for cuts and abrasions to animals, but humans also used it. They are recorded as having bought the patent for Josephson's Australian Ointment in about 1870 and continued producing it under its original name. They are also advertised as manufacturers of cordial, soap powder and vinegar as well as pharmaceuticals.

As manufacturing and importing chemists Row and Co. can be expected to have bought chemical supplies in bulk and possibly already packaged for sale through pharmacists and agricultural suppliers. They would probably have repackaged bulk materials into containers for sale, and are likely to have conducted their own manufacturing on the site. This would have therefore required storage for bulk imported chemicals, for the packaging into which it would have been then distributed, an assortment of machinery for their own production, including mixers, blenders and pill machines. These could have been hand operated or connected to a small steam engine that would have provided sufficient motive power.

Edward Row and co occupied the property until 1921, at which point they shared with another occupant for three years, and ceased occupation in 1924 after a total tenancy of 48 years. During these last few years electrical engineer Cecil Row, probably related to the Edward Row family, also occupied the residence.

A box manufacturing company, Lawley and Co. occupied the store in 1925.

In 1902 the buildings were resumed by The Rocks Resumption Board. Lots 4 and 5 were sold to the board for . The board had been established to acquire privately owned property in The Rocks for redevelopment, because the 1900 bubonic plague outbreak had proven to some that the old and poorly planned residential area provided a ready reception for disease-bearing rats from the equally old and poorly planned wharf facilities. While this was partially true, the inadequacies of the existing port facilities were recognised and plans were drawn up for a modern port, which required the Government's acquisition and consolidation of land several blocks from the waterfront. While many houses within The Rocks were demolished, the use of the Merchant's House for manufacturing, business and residential occupation continued relatively unaffected.

The Sydney Harbour Trust (SHT) gained control of the property from The Rocks Resumption Board in 1927. This was part of a continuing process of acquisition of properties within The Rocks and Millers Point that had begun when the SHT was established in 1900. Although its main purpose was not to manage properties it took on this role because of a lack of strategic direction following World War I.

The first boarding house lease was issued to Mary Grady (or O'Grady) for the combined Nos. 43–45 in 1928. Some modifications were required to permit the new form of use, and these are probably the reason for partitioning, and access being pushed through between the residence and store at each level. A bathroom was added on Level 1 at the stair landing.

Further modifications are recorded in 1934, including a new kitchen and improvements in water supply and toilet, as well as further improvements in access between the two buildings.

Mary Grady's granddaughter Joan Cubis was interviewed in the house in 1993 before the most recent conservation works took place. Joan lived with her grandmother in the house from 1928. Her grandmother had moved from Fort Street because of construction of the Harbour Bridge. Mary Grady was replaced as lessee by Haigh Zlotkowtski in 1935 who remained until 1941. The access points from No. 45 to No. 47, which had been closed off, presumably when the SHT took over, were re-opened.