At the end of the 19th century, modern commercial brands emerged after the creation of the legal framework for their protection and the birth of large commercial companies. In the Portuguese wine sector, there was a strong adhesion of companies to the registration of trademarks as a defense against practices of “abusive use of false or misleading indications of provenance”, in a context of post-phylloxera reconversion, market instability and the proliferation of imitations and counterfeits. The commercial sector took ownership of the brand in its identification with the designation of origin, leading to the emergence at the beginning of the 20th century of a movement led by prominent personalities from the Douro Region in the sense of creation of legal mechanisms to defend the regional brand of Portwine. We will analyze three historical quintas (estates) — Senhora da Ribeira, Bomfim and Zimbro — and the marks (brands, labels and fire marks) of Silva & Cosens, the “most respectable” company in the Douro wine trade in the early 20th century. We aim to undesrtand how this company created trademarks with a strongly identifying character with the Douro Demarcated Region, the producing region of its wines.