Catherine of Braganza has regularly been referred to as ‘the forgotten queen’ and there is much truth in this statement. Following her death in 1705, a fully detailed biography in English remained unwritten until 1915. The last major bio published about her was in Portuguese in 1941 and it has never been translated into English. Despite her sheltered and religious upbringing, she made a spectacular marriage that was plagued by the infidelities of her husbands. Readers can readily find published biographies of Charles II’s many glamourous mistresses, but curiously, little on his wife. This new work presents more comprehensive information on Catherine’s life in Portugal than previous biographies and integrates new scholarship regarding Catherine’s practice of queenship and patronage of Catholic Baroque culture in an effort to carve out a prominent role at the Stuart court and to compete with her rivals. Readers familiar with Catherine’s story may learn some delightful new details about her life. Catherine has never been forgotten in Portugal. She considered herself Portuguese at heart and during her reign as Queen of England, she persistently looked out for Portuguese interests. In her own words, she considered her marriage a personal sacrifice to what was best for her home country. She is one of the few dowager queens in history to return to her homeland where she acted as regent for her brother. This biography places Catherine within the context of the history of Portugal and their seaborne empire, and the strong political and commercial ties between England and Portugal dating to the mid-fourteenth century which played a key role in the culmination of the Marriage Treaty of 1661. Her legacy lives on in her dowry, specifically the port of Bombay which allowed England to become a global empire, introducing many everyday items into European culture.