[2] He already owned the Pentyrch blast furnace and several small forges when he became a partner in Dowlais Ironworks in 1759.
[3] Lewis was the partner who arranged the mineral leases and construction of the new ironworks: the works were carried out by his business, Thomas Lewis & Co.[3] He headed the business and his family interest was not bought out until 1848.
[3] He was also a partner in the firm of Coles, Lewis & Co which had interests at Melin-y-cwrt and Ynys-y-gerwn.
[4] Lewis's family had lived at Llanishen for many generations but he was responsible for building the New House there.
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